Sciencemadness Discussion Board - Gun Propellants: Single, Double and Tripple based

Gun Propellants: Single, Double and Tripple based

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Practicaler - 9-12-2012 at 08:39

Hello users of scienemadness.
Friend currently I am making various types of bullets for testing their different power . What I want to know is various types of propellants that are filled inside the bullet to give it very high velocity. .till now u could find smokeless powder double base propellants . But I couldn't find their actual composition and how to make these propellants.will anyone please tell me a very powerful propellant that can give very high velocity to bullet and how to make it please help me . Please

[Edited on 28-10-2016 by Bert]

hissingnoise - 9-12-2012 at 09:14

Few here will want to answer a question on stuff you can maim or kill yourself with when the question is couched in such k3wlish terms . . .

franklyn - 10-12-2012 at 00:44

@ hissingnoise

Oh I don't know , it is evident that English is not this person's native language.
I wonder hissingnoise how you would come across with a little help from babelfish.

@ Practicaler

Smokeless powder used in small caliber personal arms is universally nitrocellulose
with some nitroglycerine and graphite which serves to drain static electric charge
that could ignite the powder. Rate of burn is determined by the size and shape of
the grains , this will determine how soon peak chamber pressure is developed for
a given amount of powder. Producing consistent reliable propellant is not
something which can be made without specialized equipment.
See chapter 9 of Military Explosives TM 9-1300-214
http://ia701505.us.archive.org/29/items/milmanual-tm-9-1300-...

Makers of propellants provide loading data for their powders. Gun magazines
publish bibles with loading data on every imaginable cartridge.
Do not exceed amounts published before having the experience and know how
to inspect the spent brass from your hand loaded cartridges for signs of having
reached the maximum pressure. Shooting a 'proof load ' , which is a cartridge
crammed full of powder , is only done as a quality test by arms manufacturers ,
and will very quickly make a firearm unfit for use , if a cartridge has not burst
before then.

.

hissingnoise - 10-12-2012 at 13:36

Quote:

Oh I don't know , it is evident that English is not this person's native language.

Of course! That'd explain him being most active in Detritus . . .
At least he didn't get the spoonfeeding he wanted!

Practicaler - 11-12-2012 at 15:43

When bullet is fired does smokeless powder detonates or just burn extremely fast providing a great thrust and will anyone tell me how to make smokeless powder

Morgan - 11-12-2012 at 16:10

I ran across this article some time ago but it strikes me as a good example of how times have changed.
http://books.google.com/books?id=kiEDAAAAMBAJ&pg=PA200&a...

Swede - 12-12-2012 at 07:30

Smokeless powder is not an easy thing to make.

Single base (nitrocotton) or double base (added nitroglycerin) both start with highly nitrated cellulose, guncotton. Guncotton is not particularly hard to make, but keeping it stable is. Typical nitrocotton from the amateur lab will have a very limited shelf life, and can degrade into a dangerous state, which was the source of numerous fatal (sometimes devastating) accidents, when rotten guncotton exploded, such as in the magazine of a battleship.

The guncotton is turned into a colloid, using solvents like acetone and alcohols. It is then extruded under high pressure through dies, and automated machinery cuts the extrusion into rods, flakes, cords. Look up cordite.

Without an added stabilizer like diphenylamine, this propellant has the same dangers as crude guncotton.

If you really want to explore propellants, start with the grandaddy of them all - black powder.

Practicaler - 13-12-2012 at 07:37

I have already made blackpowder with mostly all the oxidizer like potassium chlorate,potassium perchlorate, nitrates ,permanganate and iodates. Just I want to know the correct procedures to make smokeless propellant or any other powerful propellant

Bert - 13-12-2012 at 07:57

You have been given links to information on how it is made. No one is going to give you a step by step instruction manual, and that's for your own good.

ScienceSquirrel - 13-12-2012 at 09:01

To be honest I doubt that you can make advanced powders without a great deal of equipment, money and effort.
These materials are very powerful and a wrongly compounded mixture could result in a serious accident.
See here for Wikipedia articles which are well referenced;

http://en.wikipedia.org/wiki/Smokeless_powder

http://en.wikipedia.org/wiki/Cordite

I suspect that even making black powder that would give adequate performance when hand loaded into cartridges would require considerable effort and depending on your jurisdiction and the licences and permits held by you might be illegal.
A quick Google on "homemade black powder cartridges" will reveal plenty of references but unless you are already experienced in muzzle loading weapons or cartridge reloading you are going to have a lot of difficulties.

ScienceSquirrel - 13-12-2012 at 15:00

I should say that this part of the forum is supposed to be about the preparation of energetic materials on an experimental basis.
The law is cloudy in most places.
But making small amounts of silver acetylide, lead azide, nitrocellulose, etc is probably legal if it is conducted on a small scale in a spirit of intellectual curiosity and there is no intention to cause an explosion.
Obviously there is a lot of latttude but making weapons like bombs and ammunition may be outside the remit of the forum.

KonkreteRocketry - 21-12-2012 at 00:54

I have a friend who like Zinc Sulfur, he make his own Zinc Sulfur bullets, when he fires, it make a beautiful flame, he told me he like it, I am not sure if it is good though..

He have his own way of grinding it into micro sizes, he uses 2 steel plates 1 little bit curved, and 1 flat, and grind the zinc into really small pieces, he showed me in microscopes it was around 1 micron only, I often go there to smash aluminium for my own interest for other fuels..

Vikascoder - 21-12-2012 at 03:30

But zinc sulfur is mostly used as rocket fuel I don't think that it is so powerful that it can give high thrust to bullet to give them highspeed

KonkreteRocketry - 21-12-2012 at 05:56

Quote: Originally posted by Vikascoder

But zinc sulfur is mostly used as rocket fuel I don't think that it is so powerful that it can give high thrust to bullet to give them highspeed

zinc sulfur have a fast burn rate therefore you can add more fuel ? I am not sure.

Ral123 - 13-2-2014 at 22:36

The biggest problem is to keep the powder from going high order. I've made 3 tests:
fuse+cotton= nice shot
fuse+azide+cotton= couldn't find a single piece of the pipe. The sound was like TNP
fuze+plasticised NC particles= a flame from the fuse hole and no bang.
If NC only doesn't go high order, I feel shooting would be pretty safe. Commercial powders generally can be set off with a modern No8 or a small booster. I want the homemade single base propellant to be that detonation resistant.

Motherload - 14-2-2014 at 09:07

In the event that you must absolutely need propellant for loading ammunition and smokeless powder cannot be procured ..... Use black powder.
You will not get nearly the same velocities but you won't blow your self up with it..
Also it will dirty up the firearm a looottt faster.
Trying to make smokeless powder at home is like trying to make modern paint for walls or engine oil for you vehicle etc at home ..... but more dangerous.

Ral123 - 14-2-2014 at 14:46

TNP can paint quite well, trust me. You can't wash it away from you fingers for weeks. Cooking oil is oil. I've used it in ball mill gears and engines. It's excellent the first months.
For non detonating propellant IMO KClO4/C/S is powerful and safe.
http://www.youtube.com/watch?v=KfzQ4uKvE7c

Vikascoder - 19-2-2014 at 23:03

If you are really testing various propellants I am curious to know your results with flash powder . Whether your gun exploded or not after using flash powder I am sure your barrel must have got heated a lot with flash powder . What's was the damage done by bullet or I mean penetration in wooden box or something like that while using flash powder pls post ur results

Ral123 - 20-2-2014 at 09:04

KClO4/C/S + a little ETN and Al. The mixture wasn't granulated, but wasn't packed tightly and reaches great pressures with the confinement of a single lead ball. Here's a real torture test:
http://www.youtube.com/watch?v=DAiK4HJ3qkk
The barrel is blown to small pieces with:
1)azide-nitrated cotton
2)black powder, setting off EGDN/NC.
Planks near the barrel were ripped.

Motherload - 20-2-2014 at 13:54

The only problem with KClO4 is it produces KCl after ignition.
KCl will cause bad rusting if the firearm isn't cleaned within a short period.
Any one who has fired corrosive mil-surp ammo will know what I mean.
The corrosive nature came from chlorate primers.

Ral123 - 20-2-2014 at 14:15

Considering the tree tests I described, I think the corrosion is the least of your worries. That mixture appears(so far) detonation resisting and quite powerful. My tests suggest a detonation can rip one's arm no difficulties.

Hennig Brand - 1-3-2014 at 16:11

These are stills from a video taken about three years ago. The homemade cannon was charged with 2-2.5g of nitrated cotton ball (nitrocellulose) and a 45 cal. lead ball. Ignition was accomplished with a bit of thin blackmatch. A small amount of black powder was also poured into the touch hole, before inserting the fuse. The piece of wood in the picture was dry beech hardwood, which is a fairly dense, tough wood. The 2-2.5g of nitrocellulose drove the lead ball through the wood very easily. Sorry, I don't remember exactly how thick the wood was.

The exit side of the piece of wood was dark from carbon because a smaller charge (~1g of nitrocellulose IIRC), was used to fire a 45 cal. lead ball at that side earlier. In that test the lead ball did not penetrate all the way through the wood. I also remember that the nitrocellulose used for both tests was not the most highly nitrated that I had ever made by a long shot.

This may be a little off topic, but I thought it was interesting. Two of the biggest reasons this test was relatively safe was because the weapon wasn't being held when it was fired and the barrel was extremely thick steel.

[Edited on 2-3-2014 by Hennig Brand]

Ral123 - 2-3-2014 at 09:23

That amount of NC is too much even for DE .50 AE. It should generate over 2000j of kinetic energy. I dream of having gun cotton that wont detonate.
You can expect high penetration in wood with copper jacketed steel ball covered in a little oil or something.

Hennig Brand - 2-3-2014 at 13:29

Yeah, it was a lot of nitrocellulose and it made a great bang. It was almost as much fun as a good detonation. The lead balls were melt/casted from lead flashing (very soft lead without antimony). The cannon was bored out for 0.50 cal., but my ball mold is 0.45 or maybe a little bigger.

IIRC, I read that one of the original NC propellant experimenters dissolved the fluffy NC in a solvent and poured it out in a thin sheet to dry. It was then cut up into little discs or particles of some kind which had much better burn characteristics and safety than the fluffy NC it was made from. I think this could be made to work pretty easily and make a reasonable propellant. This would of course just be single base propellant, so production should be a little simpler to get consistent results with than with double and triple base propellants.

Edit:
Ok, this is from someone's blog, but I read the same (or similar) passage from an older book years ago.

"In 1884, a French chemist named Paul Viellie succeeded in improving guncotton's stability issues. He discovered that by treating guncotton with a mixture of alcohol and ether, it could be gelatinized. The material could then be rolled into sheets, cut into small squares or flakes and then stabilized with a 2% solution of diphenylamine. This formulation was codenamed Poudre B by the French government and it was a closely guarded secret. This formula produces a substance that is much more stable than guncotton and it will not detonate unless it is compressed. Unlike black powder, Poudre B also burns when wet and produces about three times the force for the same volume. This was the first "single-base" powder. The French developed the 8 mm. Lebel cartridge (the first smokeless military cartridge) and a new rifle, the Lebel Model 1886 to use this new technology. "

[Edited on 3-3-2014 by Hennig Brand]

Ral123 - 2-3-2014 at 22:53

I've tried it, the plastic NC particles need a little initial kick, like from LS or may be some cotton NC. The problem is that I don't trust the home made plasticised from completely, to shoot with it. Maybe only in 5.5 pellet gun or something.
In my leave on the sun in a dark container in the summer test, the NC cotton did very well. It's just washed, but showed no signs of decomposition.

Bert - 3-3-2014 at 06:11

Quote: Originally posted by Ral123

I've tried it, the plastic NC particles need a little initial kick, like from LS or may be some cotton NC.

Are you referring to having difficulty igniting the plasticized NC?

Dense, colloided NC powders are generally a LOT more difficult to ignite than black powder, new primer compound technologies were required to go with these new propellants-

Look at primer pellet compositions intended for modern powders. Ingredients to enhance ignition from both hotter flames than the old fulminate & chlorate mix caps/primers and others to produce hot burning particles. Ingredients like Antimony sulfide, Lead thiocyanate, tetryl, PETN and TNT,

A bag of BP placed over the percussion or electric primer is used as an igniter charge for the NC propellent in a lot of artillery applications. During the transition from BP to NC, some cartridges for rifle and pistol were also loaded with BP mixed with various forms of NC, as in Du Pont's "Lesmoke" powder- They just added nitrated sawdust right into what was essentialy BP during manufacture.

Other transition period cartridges were loaded with both black powder and smokeless/semi smokeless powders together in a variety of techniques for various reasons including enhanced velocity, accuracy and improved fouling/cleaning characteristics.

http://castboolits.gunloads.com/showthread.php?137201-Black-...

[Edited on 3-3-2014 by Bert]

Hennig Brand - 2-8-2014 at 16:16

Was firing a homemade brass cannon this afternoon and I thought I would post a few pictures. Homemade nitrocellulose was used for three shots and commercial FFFG black powder was used for another three shots. The projectiles were 0.45 cal. lead balls.

Included are a few pictures taken showing the penetration of one of the shots where the homemade nitrocellulose was used. About 2.6g of nitrocellulose was used as propellant and the lead ball penetrated a 5" spruce block and two 1 inch hemlock boards. A later shot used 2.2-2.5g of commercial FFFG black powder and the ball made it less than 2 inches into the spruce block, as shown in the last picture. This really shows the incredible difference between these two types of propellants. The nitrocellulose used was not nearly as highly nitrated as it could have been either. Black powder is a lot of fun though and it does have its uses. It is much easier to make black powder with reasonably consistent performance and storage stability, than it is with smokeless powder, which is one big advantage.

2.5g Nitrocellulose Penetration.jpg - 520kB

2.5g Nitrocellulose Penetration 2.jpg - 509kB

2.2-2.5g Black Powder Penetration.jpg - 330kB

[Edited on 3-8-2014 by Hennig Brand]

NeonPulse - 2-8-2014 at 16:33

Very nice! How big is the barrel? Sure packs a punch judging by the penetration there, could you recover the round or was it shattered? I actually am working on something similar but on a much smaller scale to fire 6mm fishing sinkers Its going to be mounted on a solid lead block though. That is when time allows me to pursue the hobby....

Hennig Brand - 2-8-2014 at 17:40

The barrel is slightly larger than the 0.45 cal. lead ball projectiles. Cotton patches were used to create a tight fit between the balls and the barrel. The bottom picture on the left shows the ball, still intact, stuck to the third hemlock board. On close inspection the ball was flattened a bit, but still completely intact. I believe these balls were made from wheel weights, so antimony hardened lead.

nitro-genes - 3-8-2014 at 03:32

NC surely is a better propellant as BP regarding gasoutput etc, though the huge difference between NC and BP in your test is mainly due to the relatively short barrel. With long enough barrel and fast BP very high muzzlevelocities can certainly be reached!

Ral123 - 3-8-2014 at 05:21

As far as I know, a bottleneck from the chamber to the barrel is needed to achieve high velocities with any propellant. Nitrated cotton is awesome propellant if it wasn't for the detonation danger. I wonder if highly nitrated cotton can be used as ignitor for smokeless powder instead of lead styphnate.

Hennig Brand - 3-8-2014 at 08:05

I think typical muzzle velocities for black powder rifle is around 1200 to 1500 fps. Rifles using nitrocellulose based propellant can reach muzzle velocities of 4000 fps or even higher. The kinetic energy equation is E=1/2mv^2, so doubling the velocity will result in a 4 times energy increase. One of the main reasons black powder arms had such heavy calibers (large bullets) was because they were trying to increase the energy of the round by increasing the mass. Doubling the mass only results in double the kinetic energy for a given velocity though. They did this mostly because they were limited in the amount of velocity they could get from the black powder propellant used at the time. The other reason, in the case of ball projectiles, was that the losses due to wind resistance were much larger with a ball as compared to a conical projectile of the same mass. A larger ball, like a conical projectile, had a much better (smaller) surface area to volume/mass ratio therefore less losses due to wind resistance as well. Less losses due to wind resistance meant that more of the energy/velocity that was present at the time the projectile left the barrel of the gun was still present once it made it to the target. Ball projectiles fired from black powder muskets, etc, in years gone by often had very little energy left in them even at fairly modest ranges. I will have to dig for a reference but even in extremely long and huge naval guns, when using black powder, they were only able to obtain ranges a fraction of what could be obtained with nitrocellulose (about 8 miles range IIRC).

[Edited on 3-8-2014 by Hennig Brand]

roXefeller - 3-8-2014 at 12:38

In a simplified model, wind losses are proportional to rho*v^2, with the proportionality constant being related to the aerodynamic profile of the object and is independent of the mass of the projectile (rho is the fluid density). Ballisticians who are concerned with the final energies of the bullet will fire a heavier bullet at the same speed (requiring a higher muzzle energy) because it sees the same drag forces (and the same terminal velocity) as the lighter bullet but still has extra mass to contribute to the (mv^2)/2 kinetic energy.

Hennig Brand - 3-8-2014 at 15:51

Unless we are changing the density of the material, changing the mass will change the cross sectional area of the projectile. I don't remember doing much of this sort of thing in school, so I am learning as I go here.

The following was taken from "Engineeringtoolbox.com"

"Drag force can be expressed as:

F_d = c_d * 1/2 * ρ * v^2 * A

where

F_d = drag force (N)

c_d = drag coefficient

ρ = density of fluid (1.2 kg/m^3 for air at NTP)

v = flow velocity

A = characteristic frontal area of the body

The drag coefficient is a function of several parameters like shape of the body, Reynolds Number for the flow, Froude number, Mach Number and Roughness of the Surface.

The characteristic frontal area - A - depends on the body."

Found a graph and a table which should help compare a spherical projectile to a modern high performance rifle projectile. The graph was taken from, http://arc.id.au/CannonballDrag.html, which is a webpage that does a great job of explaining drag on spherical projectiles. The following is the text which preceded the graph.

"Drag Near the Speed of Sound

The speed range of interest for smooth bore guns is from ~100 m/sec to ~700 m/sec, since the speed of sound is ~340 m/sec, this corresponds to a range of Mach numbers from 0.3 to 2.0, so the additional forces associated with projectiles travelling near the speed of sound will be significant.

Fig 2 shows a plot of the drag coefficient as a function of Mach number for spheres ranging in diameter from 2.5 mm to 12.5 mm. The curve is a manual fit to chronograph data [Miller & Bailey, 1979]. The rapid increase in drag as a function of Mach number at velocities near the speed of sound is clear."

Small Sphere Drag Coefficient as a Function of Mach Number.jpg - 23kB

The table comes from, R.L. McCoy's Modern Exterior Ballistics, and the bullets shown are apparently common high powered rifle bullets (modern low drag bullets).

Drag Coefficients for Typical High Powered Rifle Bullets.jpg - 54kB

Energy/Work = Force * Distance = Drag * Distance of Bullet Travel

Since velocity and drag coefficient change during bullet flight, which changes the drag force, it makes for an interesting problem. Would be easy to do with a computer. Manually the bullet flight could be broken up into small increments and an average value for work done on the bullet by the drag force for all increments could be found. This would give an approximate answer with the accuracy dependant on how many increments were taken.

[Edited on 4-8-2014 by Hennig Brand]

roXefeller - 3-8-2014 at 18:08

Quote:

Since velocity and drag coefficient change during bullet flight, which changes the drag force, it makes for an interesting problem. Would be easy to do with a computer. Manually the bullet flight could be broken up into small increments and take an average value. Adding up the increments, could give an approximate answer with the accuracy dependant on how many increments were taken.

It's a nonlinear differential equation and can be solved with standard methods. Starting at F = ma, -b*v^2 = m*dv/dt, m*dv/dt + b*v^2 = 0, dv/dt + (b/m)v^2 = 0, integrating: Sdv/v^2 = -b/m Sdt - C/m, -1/v = (-bt-C)/m, v = m/(bt+C), C = m/v_o if my calculus didn't fail me. I'll let you perform the dx/dt integration for speed drop vs distance, it looks logarithmic. So if you stop and examine the b/m coefficient of the diff eq dv/dt + (b/m)v^2 = 0, overall reductions reduce the drag term (diminished b or enlarged m, or if m is increasing at a faster rate than b). Fat men coast better downhill on bikes. It is a simplified model (you could add the velocity dependence of b(v) and then go to a differential equation solver), and I'm generally referring to low drag rifle bullets where the length (mass) of the bullet means a bit less to drag than the front taper and the rear flow separation point. That explains why I was claiming that mass can increase without significant drag increase.

As far as proximity to sonic transition, rifles are generally supersonic. It is usually better to strike the target before the bullet transitions because instabilities at transition cause random variations in trajectory and misses.

[Edited on 4-8-2014 by roXefeller]

Hennig Brand - 4-8-2014 at 06:57

I should have just said to add up the losses for the increments, to get the total lose in the above quote.

This kind of thing, from what I have read in the last day or so, is generally considered very complex. Your math seems correct for the simplified model, though calculus was not my favorite subject in school. The ballistic coefficient will change a lot with velocity, as you can see by looking in the above tables, but the change does look to change fairly linearly with velocity, though the slope does change at a point below the speed of sound. With spherical projectiles the mass has a much greater effect on drag and losses than in low drag conical projectiles and spherical projectiles is what the cannon in the above test used. With spherical projectiles the ballistic coefficient is much larger in magnitude and changes much more with respect to changes in velocity than for conical projectiles, once again though the change is fairly linear apparently with respect to velocity. I guess the best way to say it, IMO, is that heavier/larger projectiles, for a given material, have more energy for a given velocity and lose a smaller proportion of their energy as a result of drag during flight. Also modern conical projectiles, mostly because of smaller radial cross sectional area with respect to mass, but also other more subtle aerodynamic improvements in shape, lose a much smaller proportion of their energy for a given distance traveled than spherical projectiles of the same mass. This all assumes all projectiles are made from the same material with the same density.

[Edited on 4-8-2014 by Hennig Brand]

[Edited on 15-9-2014 by Bert]

Dornier 335A - 4-8-2014 at 08:36

I wrote a simple Python program a while ago to simulate projectile trajectories in the atmosphere. It is based on the formula Henning Brand posted earlier:
F_d = c_d * 1/2 * ρ * v² * A
It calculates the changes in x and y velocity every millisecond. I added the air's change in density by altitude for simulations of long range artillery but not how c_d changes with speed.
I could post the code if anyone wants; it's only 30 lines or so.

Manifest - 4-8-2014 at 09:05

Quote: Originally posted by Dornier 335A

I wrote a simple Python program a while ago to simulate projectile trajectories in the atmosphere. It is based on the formula Henning Brand posted earlier:
F_d = c_d * 1/2 * ρ * v² * A
It calculates the changes in x and y velocity every millisecond. I added the air's change in density by altitude for simulations of long range artillery but not how c_d changes with speed.
I could post the code if anyone wants; it's only 30 lines or so.

Sure, why not show off your work.

Dornier 335A - 4-8-2014 at 09:28

Here's the code:

Code:


from math import sin,cos,e,radians,atan2,sqrt,pi

α = 30 #Angle of elevation (degrees)
V = 25 #Muzzle velocity (m/s)
M = 0.0027 #Projectile mass (kg)
R = 2 #Projectile radius (cm)
cd = 0.42 #Drag coefficient (0.42 for spheres)
y = 0 #Elevation (m)

x = 0
Vx = V*cos(radians(α))
Vy = V*sin(radians(α))
A = 0.0001*pi*R**2

def FD():
    ρ =  2.831/(1 + 1.3262*e**(0.1516*y/1000)) #Density of the air
    return 1/2*V**2*ρ*cd*A #Calculate drag force

for t in range(300000):
    x += Vx*0.001 #Move the projectile
    y += Vy*0.001
    Fd = FD() 
    Fx = Fd*cos(atan2(Vy,Vx))
    Fy = Fd*sin(atan2(Vy,Vx))

    Vy -= (0.00982 + Fy/(1000*M)) #Velocity changes
    Vx -= Fx/(1000*M)
    V = sqrt(Vy**2+Vx**2) #Speed
    if round(t/100,1) == t/100: #Print position every 100 ms
        print(x,y,Vy) 
        pass
    if y <= 0 and Vy < 0: #Print position when landed
        print(x,y)
        break

Hennig Brand - 5-8-2014 at 08:18

Nice bit of code you have there. I only took one first year computer science course, but it was clear even from the limited exposure I had that it was a great way to make very powerful tools for processing massive amounts of data. We mostly used Matlab in the course I took.

I just made up an Excel spreadsheet which should be useful for small cannon, etc, firing spherical projectiles. The above equation for drag force and the kinematic equations of motion were used. An equation for the ballistic coefficient was obtained from a Master’s thesis called, "Ballistics of 17th Century Muskets", by Dr. David Miller and the data and methods he used came from earlier more well established references.

F_d = c_d * 1/2 * ρ * v^2 * A

where

F_d = drag force (N)

c_d = drag coefficient (unitless)

ρ = density of fluid (1.2 kg/m^3 for air at NTP)

v = flow velocity

A = characteristic frontal area of the body

Drag Coefficient for Musket Ball.jpg - 21kB

C_d = 0.107 + 2.08*10^-3 * v

where

C_d = ballistic coefficient (unitless)

v = projectile velocity in m/s

a = F/m

where

a = acceleration in m/s^2

F = force in N

m = mass in kg

k = 1/2 * m * v^2

where

k = kinetic energy

kinematic equations

d = v * t

v = v_o + at

Volume of sphere

V = 4/3 * pi * r^3

Cross sectional area of sphere

A = pi * r^2

(Maybe a couple others too)

The values in the table assume still air (no wind), so it does not account for changes in horizontal position from point of aim, or changes in bullet velocity as a result of increased or decreased drag in the direction of bullet travel, due to this form of windage. Drag forces were not considered for projectile drop, from the point of aim, as the velocities are very small which means the drag forces would also be very small.

Time increments of 0.001s were used, but this could be made smaller if desired for greater accuracy. Loss of accuracy comes from the fact that for each 0.001s increment the value for deceleration due to drag forces was taken as the value at the beginning of the increment. The table was made for up to 0.2s of flight time, but the columns can be extended if more values were desired. It can be modified if desired, or used as is by simply changing the 5 variables highlighted in yellow. The density of lead was set as the default density for the projectile. Here is a link to a webpage with a table showing air density versus temperature.

http://www.engineeringtoolbox.com/air-properties-d_156.html

Not too hard to tell why conical projectiles, and propellants and guns capable of higher velocities were adopted. The proportion of kinetic energy lost even at very short range is incredible.

Keep in mind that the bullet doesn't travel in a straight line, but rather follows a parabolic path. The distances in the table are the distances along that parabolic path. The actual horizontal range will be somewhat less, if the gun is pointed above the target (which it must be). For normal short range shooting, the angle would be so small, that the difference in distance between the true parabolic path and an assumed straight path to the target would be quite small. Likewise, because the angle is normally so small, the component of the muzzle velocity in line with the target would normally be nearly the same as the full muzzle velocity.

It is possible I have made errors, if so let me know.

Attachment: Spherical Projectile Velocity & Position Table.xlsx (74kB)
This file has been downloaded 1306 times

Attachment: Spherical Projectile Velocity & Position Table (compatibility mode).xls (138kB)
This file has been downloaded 1209 times

[Edited on 6-8-2014 by Hennig Brand]

Hennig Brand - 12-8-2014 at 04:00

Quote: Originally posted by Hennig Brand

C_d = 0.107 + 2.08*10^-3 * v

where

C_d = ballistic coefficient (unitless)

v = projectile velocity in m/s

C_d should have been called drag coefficient, as it was above. I assumed that they were the same thing, which they are not apparently.

Hennig Brand - 15-8-2014 at 08:52

Just noticed that I forgot to take the average velocity for each increment when calculating projectile drop. Just made the minor adjustment and attached the revised tables.

Attachment: Spherical Projectile Velocity & Position Table (Revised).xlsx (74kB)
This file has been downloaded 1148 times

Attachment: Spherical Projectile Velocity & Position Table (Revised & Compatibility mode).xls (138kB)
This file has been downloaded 1239 times

[Edited on 15-8-2014 by Hennig Brand]

roXefeller - 15-8-2014 at 13:23

The topic of where in the increment you are integrating in the summation is a topic of numerical methods theories. In explicit integration schemes this choice can affect the stability of the solver for a given increment. There is a certain amount of 'damping' of the solution error that each position in the increment creates. It's an interesting aspect of numerical integration of ordinary differential equations that are a function of time. That's a long winded way of saying, just because you 'feel' its somehow wrong the way you did it before, it is only one of many options for this technique. Something to remember, 'all models are wrong, but some models are useful'.

Hennig Brand - 15-8-2014 at 14:12

I see what you mean. I know that the model isn't perfect, but I think using an average velocity over each increment will increase accuracy.

roXefeller - 15-8-2014 at 17:21

That is a difficult term to describe though. Since your hoping that a result matches reality, that should be said explicitly. Obviously we know that the numeric solution is incorrect, either to one side or another of the true answer. And you attempt to hit the mark by your own feel good, best estimate, engineering judgement approach. So at the end you reason to yourself that one improvement is more accurate than before, based, tacitly, on how you feel the problem is setup, instead of qualifying your answer against reality. But it can be that the errors 'introduced' can actually offset the error inherent in the integration scheme and in the end, though you feel the answer is less accurate because you knew it wasn't the best attempt, the math and the comparison to reality says otherwise. I know this sounds ethereal and like a conspiracy theory, but what I'm getting at is a more fundamental point; you need to base your conclusions in the end less on the subjectivity of your opinions, and more on the objectivity of comparison to truth. An analyst can be fooled by a simulation, test technicians are less so.

Here is the text book example from numerical methods 101: when you compare the zero, first, and second order numeric integration schemes, each one has its own error approximation. The math is more complicated with each additional order, going from point approximation, to line, to quadratic approximation of each finite step along the path. The gut instinct is that error is reduced going from zero to first, and reduced further going from first to second because each interpolant function more closely adheres to the function you are trying to integrate. When in fact the error in the zero order scheme is the same as that in the second order, and the first is worse than both. You'd be better off sticking with the zero order scheme or skipping the first and going to the second according to the error approximation. I've got other examples that aren't so basic but that one is a good starting point. I feel like I'm saying something Rosco has been telling us repeatedly over the last year, except mine has less elegance. Something about the conflict of truth and the opinion of the experimenter.

Hennig Brand - 15-8-2014 at 19:50

If I use the kinematic equation of motion below to check the vertical drop due to gravity, neglecting air resistance for the 0.2s of flight time, I get a total drop of 7.72441 inches. In the first table I didn't take the average velocity for each increment and the total drop came out to 7.76303 inches. In the revised table I used the average velocity over each increment to calculate distance travelled (dropped) and got 7.72441 inches, or the same (at least to the amount of decimals shown) as that obtained when using the kinematic equation below, which is an improvement. The difference isn't huge, but there is a difference. The biggest source of error in that part of the model, IMO, was that drag wasn't considered (constant acceleration was assumed), but even that error would be pretty small given the low drop velocity the projectile attains in the short flight time.

d = v_ot + 1/2at^2

Now that I am looking at the table again, I could have done it neater by just using the kinematic equations entirely, but instead I reasoned through it in my own way. What I did would simplify to the same thing though anyway I think.

I may have dodged the hard math by using a spreadsheet to work this out, but I think that table would be of much more use to most and the variables are easily changed as needed producing a whole set of values. I do see where the kinematic equations come from too, using basic calculus.

[Edited on 16-8-2014 by Hennig Brand]

Down the Rabbit Hole a Little Farther

Hennig Brand - 17-8-2014 at 14:11

I spent a few more hours reading and playing around with the ballistics table and I think it is starting to become a much better model (more accurate representation) . Launch angle of projectile was added as another variable and the velocity was broken into vertical and horizontal components. Drag was included in all velocity calculations. I used some of the equations from the NASA site for projectile motion with drag, and one equation from the Wiki page on drag for velocity of a free falling object through a non-dense medium. Conditional formatting was used so that when the projectile vertical velocity is at zero, at maximum height (at end of ascent), the following values (during descent) are calculated using the equation for a projectile in free fall. I think there should be more conditional formatting for that column, actually, because during ascent, at very low vertical velocities, especially with low launch/firing angles, the drag force is proportional to velocity not the velocity squared. I may look into it at a later time.

I made a pdf of the NASA page for my own notes, and included it here. I hope they don't mind. It is a very good resource they provide, with excellent explanations to go with the equations. The equation taken from the Wiki page for vertical velocity of free falling objects including drag is as follows:

V_(t) = sqrt[(2*m*g)/(density_air * A *C_d)] * tanh[(t*sqrt{(g*density_air*C_d*A)/(2*m)}]

From Wiki: "The velocity as a function of time for an object falling through a non-dense medium, and released at zero relative-velocity v = 0 at time t = 0, is roughly given by a function involving a hyperbolic tangent (tanh):"

BTW, I included a couple of graphs, one in metric (meters and cm) and one in Imperial or American units (feet and inches). I use both pretty much interchangeably, but some don't. In school they had us use both. One of my first year professors, who happened to be teaching statics and dynamics said that needing to use both sets of units was the consequence of living next door to an eight hundred pound gorilla. I thought it was funny especially since the gentleman was from Texas.

Attachment: Flight Equations with Drag.pdf (116kB)
This file has been downloaded 1427 times

Attachment: Spherical Projectile Velocity & Position Table (Revised again).xlsx (202kB)
This file has been downloaded 1114 times

Attachment: Spherical Projectile Velocity & Position Table (Revised again & Compatibility Mode).xls (322kB)
This file has been downloaded 1379 times

Feels like I am back in school. I only took first year statics and dynamics for engineers. I guess the physics and mechanical engineering people would have done more. It is pretty fun stuff.

Graphs of projectile position during flight can be found by scrolling to the right of the tables, in the Excel files. The flight time displayed by the table was extended from 0.2s to 0.5s, and it can easily be extended more.

If I can get out of the city for a while I may get to do a little testing and see if I can actually hit anything using this table.

BTW, if one of us could design a good hand held laser gun it would sure simplify things.

[Edited on 18-8-2014 by Hennig Brand]

Hennig Brand - 22-8-2014 at 07:15

I have been looking into getting a ballistic chronograph so that muzzle velocities can be measured. Without a reasonably accurate value for muzzle velocity a ballistics table is of little use. For now I found these equations, from the following website, which allows one to obtain an estimated muzzle velocity through calculation for black powder, smooth bore, cannons.

http://arc.id.au/CannonBallistics.html

I have attached a jpg of the final two equations, but if you go to the site there is a description, with intermediate equations, of how they arrived at the final equations. There are also tables comparing calculated performance values and actual performance values for black powder cannon. The calculation results are, at least from what has been reported, fairly close to actual field results in most cases.

In the equations,

m = mass of cannon ball
p = mass of black powder charge = pi/4*d^2*c*n
where n = density of powder charge, d = bore diameter
c = length of black powder charge
L = full barrel length

Note: Units do not matter as long as you are consistent when using the equation. If using lbs stick with lbs, if using ft stick with ft, etc. The mass units are specified in the Excel sheet, however, since the units for the mass of the projectile were already set from earlier calculations.

These equations only produce an estimate, but the results obtained should be reasonably accurate in the absence of a chronograph. Accuracy of these equations is something else to test once I have a chronograph.

The Excel tables have been updated again, this time they include the muzzle velocity calculation. The muzzle velocity value obtained, if this method is used, still needs to be entered into the user controlled variables column however.

Black Powder Smooth Bore Muzzle Velocity Equations.jpg - 74kB

Attachment: Spherical Projectile Velocity & Position Table (Revised again again).xlsx (181kB)
This file has been downloaded 1157 times

Attachment: Spherical Projectile Velocity & Position Table (Revised again again & Compatibility Mode).xls (285kB)
This file has been downloaded 1289 times

[Edited on 22-8-2014 by Hennig Brand]

Hennig Brand - 10-10-2014 at 06:54

I made some homemade smokeless powder a few weeks ago. The powder was made very much the way Poudre B was made except that ~2% Vaseline was used in place of the 2% paraffin. Wikipedia has a good page describing Poudre B and the other smokeless powders.

http://en.wikipedia.org/wiki/Smokeless_powder

First cotton balls (~5g worth) were nitrated with a mixed acid made from 50g of fertilizer grade ammonium nitrate (dried) and 90 mL of 91% sulfuric acid. The glass vessel was lightly sealed and the cotton allowed to nitrate for 24 hours at room temperature in the dark. The nitrocellulose was then removed from the nitration bath and washed very well several times with warm water and then soaked in a warm 4-5% sodium bicarbonate solution. The nitrocellulose was then dried at room temperature over the course of a few days. Drying time can be significantly reduced by using moving air and/or heat. If using heat the temperature should not be allowed to go over 60C from what I have read. If I make much of this stuff I am going to build a dryer which will force warm air (<60C) through the nitrocellulose in a drying chamber.

The NC was next dissolved in acetone and the Vaseline was added with mixing. The "NC lacquer" was next poured out on a piece of waxed paper, in a thin layer, and allowed to dry until it was mostly dry, but still soft. While it was still slightly soft it was cut up on a cutting board using a rolling type cutter with several cutting wheels. The propellant becomes very hard and difficult to cut when completely dry. I picked up the rolling cutter for $1 at a thrift shop. For doing large quantities a motorized machine or something with a hand crank that the smokeless powder sheets could be fed into would be much better, but this works for small quantities.

BTW, the smokeless powder on the cutting board, in the first picture, was from an earlier batch where about 2% of black powder was added to the mixture to increase flammability. Since the same vessel was used to mix the next batch the small amount of black powder left in the vessel gave a slight gray tint to the next batch (which was what was used in the 410 shotgun test).

Some of the smokeless powder was first tested in a homemade 0.45 cal. cannon, where the powder was lit by Thermalite fuse. The results were not good at all, in spite of Thermalite being a very hot burning fuse, which was not all that surprising. On ignition, there was a tiny pop and then three quarters of the powder was spread out in front of the cannon for two or three feet. The cannon ball was found about three feet from the muzzle on the ground. As was discussed earlier in this thread, smokeless powders require a very hot/fast ignition like is produced from a primer.

The next test involved putting some of the homemade smokeless powder in a shotgun shell. The #4 shot, wadding and the 1g load of commercial double base propellant were removed from a 410 shotgun shell and then reloaded with the same weight of homemade propellant (1g). Two shots were fired at a piece of 3/4" plywood; one containing the homemade propellant and one unaltered shell containing the commercial propellant. The homemade propellant worked very well when ignited with a primer. It didn't appear to produce as much damage as the commercial powder, but I messed up the test a bit by not standing at exactly the same distance from the target when firing, which changed the grouping from shot to shot. The tighter grouping (balls closer together) in the shot involving the commercial propellant would have resulted in better penetration, all other things being equal of course. Also the commercial propellant had grains that where many times smaller than the grains of the homemade propellant, which would make a huge difference in the burn rate. Smaller grains burn faster. I think the burn rate is especially important in this case given the extremely short barrel on the 410 shotgun used.

Even though it seems to be conventional wisdom all over the internet that smokeless powder is too hard to make for the amateur, I do not believe that it is really that difficult to make a useful smokeless powder. It must of course be very well neutralized of all acidity and be properly stabilised, if it is going to be stored for any length of time. Commercial powders have great consistency from batch to batch, which will be hard to match for the amateur, but I have an answer for that too. Once a process is well established an amateur should be able to produce reasonably consistent results, then using a chronograph and the gun that will be used the powder can be standardized. Once a batch is standardized the load weight can simply be adjusted slightly to account for slight differences in performance from batch to batch. This should allow the loader to produce a consistent muzzle velocity, for a particular gun, from batch to batch. In the case of a shotgun load, producing a precise muzzle velocity is normally not a real necessity anyway. High performance rifle marksmanship requires very precise propellant and everything else.

I will be saving my empty shotgun casings from now on. The spent primers can be easily removed and a new primer reloaded. Shotgun primers are also not expensive, from what I have seen. I have a lot of good information at this point on making homemade primers, but unless it was a necessity to make my own I think I will continue to buy primers.

From earlier batch:

Reloading a shell:

Shell Loaded with Homemade Smokeless Propellant.jpg - 461kB

Shot when fired with homemade propellant:

Shot when fired with commercial propellant:

Commercial Powder Front View.jpg - 432kB

[Edited on 10-10-2014 by Hennig Brand]

Praxichys - 10-10-2014 at 08:00

Maybe look into a noodle-plate type extrusion device to get consistency in your grain size. You would just need to force the paste through a plate full of small holes, and knife off the 'noodles' periodically. A big syringe and some steel bits might even work, albeit being tedious.

Or perhaps grind it somehow and classify the powder by screening.

A ballistic chronograph is easy. Just fire the charge into a pendulum of known mass and record how far it swings back. Knowing gravitational acceleration, you can work back the V_i of the box+projectile, and using the mass if the box you can get the V_i of the projectile. A ~30cm plywood cube full of wet newspapers would stop a 410. Just weigh it before the test.

You could also rig the shotgun up on a sling, trigger it remotely, and record how far back it swings on recoil. If you know the mass of the shotgun and the projectile, gravitational acceleration, you can get the projectile velocity. Triggering without disturbing the setup might be accomplished with a small rubber bladder in the trigger guard with a thin hose leading to a compressed air source.

All speculation. Food for thought. Great work though. Do be careful.

Hennig Brand - 10-10-2014 at 08:33

The extrusion idea is not a bad one and it is how it is done commercially IIRC. I was thinking of some kind of rotary cutter with rollers for feeding the sheets into the cutter powered by a hand crank (or motor). The cutting wheel/roller could have little cutters that would take little bites of the required size out of the sheet as it was fed in. The grains would fall into a collection bin.

I am familiar with the ballistic pendulum. I actually just bought a Shooting Chrony a month or two ago, and have tested the muzzle velocity of just about every gun and load within reach since then.

[Edited on 10-10-2014 by Hennig Brand]

Bert - 10-10-2014 at 09:29

Pasta maker-

The roller part of the machine also works quite well for processing plastic explosive materials, rather easier than rolling a wine bottle over a sheet of plastique for hours on end.

gregxy - 10-10-2014 at 10:41

Shotguns use the fastest burning powers so you are relatively safe performing this type of experiment with a shotgun. Rifles use slow burning powder so if your home made powder burns faster than the original you will blow up your rifle.

There are computer programs like Quickload which simulate the combustion of powder in the chamber, the pressure generated and calculate the acceleration of the bullet. It becomes quite complicated since the burn rate is proportional to the pressure in the chamber and many other factors like the grain size.

Powder makers do things like adding graphite to the power to block the penetration of infrared radiation which slows the heating of the grains and the burning process. It becomes very complicated.

I wanted to convert my cap and ball black powder revolver to smokeless powder so I calculated the correct load. The original was about 25 grains of black powder, the calculated load was 6 grains of smokeless powder suitable for a 9mm handgun. I needed to keep the pressure below 10,000PSI since it is what the gun is designed for. Modern guns use much higher pressures. The ability to use smokeless would be nice since is does not leave residue that makes it hard to clean the gun.

However I found that the cap could not ignite the smokeless powder
(even though it pushed the bullet 1/2 way down the barrel). So I added a small piece of magicians flash paper (nitro cellulose). The gun would now fire (weakly) but there was still a bunch of unburned powder left in the
barrel. The large chamber volume and low sectional density of the
spherical bullet work to keep the pressure low, apparently too low to burn
this particular smokeless powder. Maybe a faster powder intended for a
shotgun would work.

Hennig Brand - 10-10-2014 at 15:40

By controlling the viscosity of the NC lacquer, by adjusting the amount of solvent used, it can be made to form the correct thickness by simply pouring it out onto a flat surface. Nice pasta maker; I imagine it could definitely be made to work. The grain size of the commercial propellant which came out of the 410 shell was really very small. I have never made more than about a quarter pound of plastic explosive at a time, so the amount of kneading was minimal (15 minutes maybe), but for larger amounts some decent equipment would definitely be a huge labor saver.

The same smokeless propellants that are used in shotguns are very often used in handguns as well, from what I have seen. The single base propellant that I made has relatively large average particle size, so I would imagine it would be safe to test in a rifle. Modern rifles are also normally extremely overbuilt in terms of their ability to withstand pressure. I really don't think that what I am doing is all that dangerous. Once the NC is no longer in the fibrous form, and given the correct load, it really is very safe material to fire in a gun. This extreme improvement in safety was what was so revolutionary about Poudre B; that coupled with the much greater performance and almost no smoke production as compared to black powder. It would be a good idea to examine the grain size of typical commercial rifle powder, specified for the particular rifle used, and also to start with lighter loads when testing homemade propellant however.

I don't think I would want to go anywhere near the maximum pressure that a gun could withstand. Black powder guns, especially the older ones, were usually made of much lower strength materials than the modern smokeless propellant types. Being out here in the country, I would tend to test my powder by simply seeing how it performs in a gun. The percussion caps made for black powder guns are much weaker than the caps made for modern smokeless propellants. I thought the reason for the graphite coating on propellant grains was to prevent static electricity sparks from igniting the propellant.

[Edited on 11-10-2014 by Hennig Brand]

Hennig Brand - 19-10-2014 at 08:26

Another batch of single base propellant was made from the same batch of homemade nitrocellulose. The propellant was cut up finer this time and loaded into 410 shells. One shell had the original #4 lead shot and the other was loaded with copper coated BBs. One gram of powder was used in each shell. The results were counterintuitive; there seemed to be less penetration even though the powder was finer. The balls were only just embedded in the target.

Projectiles for Single Base Test.jpg - 469kB

Next, a batch of nitrocellulose with a low level of nitration that was made two years ago was used to make a double base propellant. The nitrocellulose was dissolved in acetone and then nitroglycerine was added. The composition of the propellant was 60% NC and 40% NG. Even though the nitrocellulose was much weaker than the nitrocellulose used for the single base propellant, the double base propellant was very powerful. A one gram load of the homemade propellant seems to have produced similar results as the commercial load when fired at the 3/4" plywood target.

The upper hole, in the following pictures, is from the earlier test with the original powder load (1g of commercial double base powder). The lower hole is from the later test using 1g of homemade double base. The factory load of #4 lead shot was used in both tests.

Homemade Double Base Smokeless Propellant.jpg - 392kB

Homemade Double Base Test Front View.jpg - 446kB

Homemade Double Base Test Rear View.jpg - 440kB

The single base propellant should have performed much better, I think. It is obviously much more difficult to synthesis nitrocellulose with a high level of nitration than it is to synthesis nitroglycerine. It is also much easier to neutralize residual acidity from NG than it is from NC. NG can be made with much greater acid economy as well, especially if the spent acids are not recycled. I definitely see some of the advantages of double base propellants already.

[Edited on 19-10-2014 by Hennig Brand]

Hennig Brand - 22-10-2014 at 11:12

The attached tables were taken from the text, “Chemical Analysis of Firearms, Ammunition, and Gunshot Residue” by James Smyth Wallace. The tables list the formulas for many common single base and double base smokeless propellants, which I thought would be very useful to someone making their own propellants. The chapter before the one on propellants is on primers, which is also very interesting. Many primer compositions are listed, often with a bit of description including history of use. The text can be found online.

Attachment: Single and Double Base Propellant Composition Tables.pdf (243kB)
This file has been downloaded 1894 times

Hennig Brand - 25-10-2014 at 09:44

A test was just performed using a single shot .22 cal. rifle and .22LR rounds with 40 grain bullets. The 0.1g of commercial double base propellant was removed from one of the rounds and replaced with 0.1g of the homemade double base smokeless propellant. The homemade propellant was screened using a small kitchen sieve to get reasonably fine grains (the commercial stuff was very fine). The homemade propellant outperformed the commercial propellant by a significant amount. The factory load gave a muzzle velocity of 1220 fps, while the homemade propellant produced a muzzle velocity of 1329 fps. Muzzle velocities were measured with a ballistic chronograph.

Sizing Double Base Propellant.jpg - 241kB

Commercial Double Base .22LR.jpg - 467kB

Here is the result of a test using a round which was hot-loaded with the homemade double base. Instead of 0.1g, 0.11g was used. The muzzle velocity of the bullet was measured as 1437 fps. Now we are really zinging. I don't think I will try and cram any more powder into the tiny .22 cal. cartridge, though I am sure I could bring the muzzle velocity up to 1600 fps if I really wanted to.

Homemade Double Base Hotload .22LR.jpg - 500kB

I have included a picture that I meant to post earlier showing the rolling cutter and propellant on a cutting board. The propellant on the board is homemade single base from earlier tests. The double base propellant, when still slightly damp with acetone, can be cut up very quickly (few minutes) when done in small quantities at a time (6-10g for example).

Single Base Propellant Cut Up With Rolling Cutter.jpg - 374kB

[Edited on 26-10-2014 by Hennig Brand]

Dornier 335A - 26-10-2014 at 11:38

That's impressive. Why does your propellant perform better than the commercial one? Is it the grain size, or the fact that yours doesn't have other additives that dilute it?

Hennig Brand - 26-10-2014 at 15:55

Thanks, particle size and lack of diluents could both be factors. Changing particle size, even while keeping everything else the same, can have a big impact on muzzle velocity. I think most samples of nitroglycerin tend to be fairly pure, however, there can be a lot of variation in the level of nitration or strength from sample to sample with nitrocellulose. The same simple separation and purification processes that exist for nitroglycerin are not possible with nitrocellulose. Nitrocellulose also normally makes up the largest proportion by weight of smokeless propellants (60% in my case). A higher proportion of nitroglycerin would normally make a smokeless propellant more powerful as well. It is very possible that the commercial propellant has less than 40% nitroglycerin.

Some of the additives/diluents, like a good stabilizer, are very important if the propellant is going to be stored for any length of time; especially if it will be stored in any quantity.

Rosco Bodine - 26-10-2014 at 16:09

Have you tried nitration of microcrystalline cellulose to produce a single base NC powder that is usable without subsequent granulation? This might also provide a good starting material for double based ball powder of very fine mesh size.

Hennig Brand - 27-10-2014 at 04:17

I haven't tried it, but it does sound like a possible way to get useful grain size without the need for granulation post reaction. It could be hard to properly incorporate the stabilizer if the nitrocellulose isn't colloided and the stabilizer isn't dissolved in the solvent though. I have never made microcrystalline cellulose, but I am interested in it. I remember seeing the thread(s) with what looked like fairly simple processes for producing MCC for the hobbyist.

specialactivitieSK - 28-10-2014 at 00:17

Smokeless rocket propellant :

DEGDN : 45 %
NC /12,5%/ : 53 %

[Edited on 28-10-2014 by specialactivitieSK]

Estimation of Percentage Nitrogen

Hennig Brand - 5-11-2014 at 10:19

Some more cotton was nitrated.

Materials:
9.8g Cotton Balls (oven dried for 60 minutes at 110C)
100g NH4NO3 (oven dried fertilizer grade)
180mL H2SO4 (91% drain cleaner)

Cotton was allowed to nitrate in the mixed acid for about 48 hours in a lightly sealed vessel at room temperature and in the dark. Post nitration, the product was well washed and allowed to soak in dilute sodium bicarbonate solution for 48 hours before being well rinsed with clean water again.

Yield:
15.96g (dried at room temperature until weight ceased to decrease)

According to the text "Military Explosives", cotton oven dried at 110C would have a moisture content of about 0.5wt%. Cotton which is not oven dried can easily contain 5-7% moisture content. Using the table in the following patent the moisture content of the air dried, at room temperature, nitrocellulose should be approximately 2-2.5wt%.

Attachment: Patent With Nitrocellulose Moisture Contents US2312741.pdf (275kB)
This file has been downloaded 1431 times

Compared to using a nitrometer the following method of determining percentage nitrogen is fairly crude, however it is a simple method to implement and it should provide a useful approximation.

Theoretical maximum percentage nitrogen 14.14%; C6H7(NO2)3O5 is the formula for the monomer.

Nitrocellulose trinitrate monomer MW: 297 g/mol
Cellulose monomer MW: 162 g/mol
Assume oven dried cellulose had 0.5wt% water content.
Assume ambient air dried nitrocellulose had 2wt% water content.
Assume that other than water the cotton feed and nitrocellulose product had no impurities.
Assume no losses due to oxidation or loose fibers poured out during washing.

Approximation of Percentage Nitrogen:

Theoretical Yield
0.995 * (9.8g / 162g/mol) * 297g/mol = 17.88g

Percentage Nitrogen
0.98 * (15.96g / 17.88g) * 14.14%N = 12.37%N

About 16g of Fibrous Nitrocellulose.jpg - 390kB

Found the following pdf online, which I thought might be useful. It is a brief overview of a nitrocellulose manufacturing process.

Attachment: Nitrocellulose Manufacturing Process.pdf (64kB)
This file has been downloaded 2239 times

[Edited on 6-11-2014 by Hennig Brand]

Hennig Brand - 8-11-2014 at 05:11

This should have been included in the last post, but I didn't think to do it at the time.

A simple burn test was performed using less than a gram of the above nitrocellulose product loosely balled up. It burned extremely fast with a huge whump sound and made a very large fireball which burned all of the hair off the fingers of the hand holding the wooden match. I was a little surprised at how fast it burned given that the percent nitrogen was estimated to be only about 12.4%. I suppose 12.4% is not really very far from 13% though. From what I have seen nitrocellulose with this level of nitration makes perfectly serviceable smokeless propellant, especially if used in a double base formulation with nitroglycerine.

TGT - 10-11-2014 at 16:04

Hennig Brand, I am thoroughly interested in this thread and am amazed what you have achieved so far. I really never thought smokeless powder comparable to factory could be made at home. Closest I have got to gun propellant is black powder lol.

One thing I wanted to mention, if you wanted to try using microcrystalline cellulose and don't mind the trouble, you can extract it from certain brands of ASA that only contain that one additive. I currently have about four ounces of it from making picric acid. Just a thought. Keep up the great work, I am extremely interested.

TGT

Microtek - 11-11-2014 at 02:31

Microcrystalline cellulose is extremely easy to make yourself. Just hydrolyse cotton wool with dilute hydrochloric acid (IIRC 10 % HCl was best). It takes a couple of hours at ca. 90 C, and then you just filter and wash the product.

Hennig Brand - 11-11-2014 at 04:30

I suppose microcrystalline cellulose would likely be easier to nitrate than a big fluffy piece of cotton. Mixing should be much easier for one.

Just found the following in the "Tri-Nitrocellulose" thread. I believe I read this thread several years ago and just forgot about it.

Quote: Originally posted by Rosco Bodine

Microcrystalline cellulose should be easily nitratable , but I have never seen it described . IIRC , cellulose flour is what is the name for it as a food additive and it is soluble like starch , but has a small number like 8 cellulose units which has a crystalline form . There are small bottles sold as a dietary supplement ,
" soluble fiber " type of material for an inflated price . But the same material is sold cheaply in bulk as a thickener additive for foods , similar to rice and potato flour .

Quote: Originally posted by ordenblitz

Roscoe,

You are correct that microcrystalline cellulose is easy to nitrate, much easier in fact since it is more dense that cotton and you can get more in the mixed acids. You can stir it more effectively and it nitrates faster since the small crystals are better exposed to the acid. After nitration is complete, leaving it to stand causes the MCNC to float to the surface of the acid in a dense layer that can be pulled out of a beaker in virtually one chunk. This brings along less spent acid and allows faster quenching thus keeping the N content as high as possible. Stabilization is a breeze as well since MCC does not have the tubular cellulose structure that cotton has therefore it traps less sulfuric acid esters. A short boil is all that's needed. The best thing about MCNC is that it retains the physical characteristics of MCC. It compresses very well in a hard and durable plastic form. Tabletted material looks very much like ivory.

I know a little bit about this since a while back, I applied for a patent on MCNC. They are slow at the USPTO it's not even in the pending list yet. My last patent took 1.5 years to show up on the website after filing.

[Edited on 12-11-2014 by Hennig Brand]

Estimation of Percentage Nitrogen Correction

Hennig Brand - 13-11-2014 at 09:55

I made a mistake in the above percentage nitrogen estimation. There was a week between when I performed the post reaction workup and when I actually did the reporting. I simply forgot, and forgot to write down, that I didn't add the last couple pieces of cotton that were weighed out so the amount of cotton nitrated was slightly less than reported. The method itself is still correct. Another experiment was just conducted where 4.99g of the same oven dried cotton was nitrated in the same way but for only 35 hours (which I believe is still a long time past the point of diminishing returns so to speak). A room temperature, air dried, yield of 8.52g was obtained which corresponds to 12.97%N estimated using the calculation from the first post. I also found some rough notes for several other nitrocellulose syntheses that were conducted over the past few years, using essentially the same grade of ammonium nitrate and the same concentration of sulfuric acid, and yields corresponded to percentage nitrogen values between 12.8 and 13.05%N in all cases. In those earlier nitrations the cotton was not oven dried, so the cotton was assumed to contain 5% water instead of 0.5% (assumed value for the oven dried cotton).

I also noticed that using significantly less nitration time, less sulfuric acid and ammonium nitrate, than what was used in the above example, still produced about the same level of nitration. I believe I switched to using larger amounts of sulfuric acid and ammonium nitrate because it made the process easier and also because it was felt that the level of nitration might be higher. I believed that extra time, especially when using a nitrate salt instead of HNO3, would increase the level of nitration (this is true up to a point). Here is a link to a couple of yields reported back in 2011 by me in another nitrocellulose thread.

http://www.sciencemadness.org/talk/viewthread.php?tid=13957#...

I knew that percentage nitrogen value seemed awfully low.

Sorry about that.

[Edited on 13-11-2014 by Hennig Brand]

Rosco Bodine - 13-11-2014 at 10:39

The microcrystalline nitrocellulose would seem to be promising for making extremely fast small mesh powders for small caliber pistol or small caliber rimfire loadings which may be able to tolerate hotter loadings that could damage larger caliber arms. This might even be a niche application for PETN based or hybrid double or triple base mixture powders as a way of increasing energy for small caliber loadings using hot loads that would not be tolerated in larger caliber arms. There has been commercial development of hotter and hotter powders for rimfire .22 and .22 magnum and there is an even smaller BB or .17 caliber rimfire.

Hennig Brand - 13-11-2014 at 11:35

Assuming that a stabilizer such as diphenylamine needs to be added to a microcrystalline nitrocellulose powder; do you think that simply washing the powder with a solution of the stabilizer might be acceptable?

Rosco Bodine - 13-11-2014 at 11:51

What are the long term storage stability characteristics for microcrystalline nitrocellulose I don't know. It may be easier to stabilize it since it already has higher purity from synthesis and less inherent instability caused by impurities or occluded acidity. So something like a betaine or cyanoguanidine solution soak and drying may be sufficient stabilization if stabilization is even needed. Testing is really the only way to find out what is needed and what works.

Hennig Brand - 14-11-2014 at 03:04

Wow, what a great thread! Here is a link to the "Tri-Nitrocellulose" thread, where the couple quotes above were taken from, and where microcrystalline nitrocellulose is discussed in depth.

http://www.sciencemadness.org/talk/viewthread.php?tid=1007&a...

Ral123 - 15-11-2014 at 05:54

I don't know how one can get completely rid of the H2SO4 in the NC. I wonder if NC can be made with HNO3 only(with less yields then RDX or PETN). Such cotton I guess will be very easy to purify and stabilize. Do you think such cotton can be used instead of lead styphnate, as a kick starter in fuse cannons or as last option for blast cap base charge(I'd say the power is between AP and TNP)?

Rosco Bodine - 15-11-2014 at 07:20

sulfoester free nitrocellulose is possible

see this linked post for a patent US2776965
for the manufacture of sulfoester free nitrocellulose , where no sulfuric acid at all is present in the nitration mixture , but magnesium nitrate is used in the place of sulfuric acid as a substitute dehydrating agent.

http://www.sciencemadness.org/talk/viewthread.php?tid=4701&a...

Hennig Brand - 15-11-2014 at 08:09

According to COPAE and other sources it is impossible to completely remove residual acidy, and other contaminants produced during the nitration, from nitrocellulose without additional special techniques that go way beyond simple washing. This is true at least for traditional nitration methods. Nitrocellulose fibers are tubular in structure which act like little capillaries locking in residual acidy and preventing its removal by simple washing and neutralization techniques. COPAE describes mechanical methods which process the nitrocellulose in such away so as to open up the fibers exposing the interior more which then allows the removal of the impurities by washing and boiling processes. The text, "Military Explosives", describes a poaching process where the nitrocellulose is boiled in a dilute sodium carbonate solution (2% solution IIRC), which as well as removing acidity is supposed to break down and remove other impurities produced during the nitration (other esters, etc), which would otherwise lower stability. I have kept several samples of highly nitrated cellulose in small quantities for a couple years or more and have always noticed that it is significantly degraded in a matter of months even though it was extremely well washed and the residual acidity (at least on the exterior of the fibers) was neutralized.

One very nice property of microcrystalline nitrocellulose is that it apparently does not have the tubular structure and so is very easy to wash and stabilize. This is discussed in the thread I just linked to in the last post.

I don't know how well nitrocellulose would work as a base charge, but the microcrystalline nitrocellulose type would likely have the best chance of performing well. From reading "Military Explosives", it seems that nitrocellulose can be at least as powerful as TNT when used as a detonating explosive. Not entirely sure how even MCNN would perform in the small diameter of a blasting cap though. I may give it a try. The percentage nitrogen and purity of RDX, PETN and NG, for instance, can be easily increased to very near the theoretical maximum by very simple washing and recrystallization techniques which remove lower nitrates and other impurities. These simple purification processes are not possible with nitrocellulose mostly because it is a polymer from what I understand. This makes production of high nitration level and high purity nitrocellulose relatively labor intensive/difficult and expensive. Nitrocellulose makes fantastic propellants though.

Dornier 335A - 15-11-2014 at 08:46

There is one plausible way of neutralizing nitrocellulose I've been thinking about. A dilute acetone solution of nitrocellulose poured into water will precipitate the NC as very fine particles and threads. If the water has been made slightly alkaline with sodium carbonate for example, all the acidic residues inside the fibres should be neutralized.

I know that Plante1999 recommended boiling nitrocellulose in dilute urea solution instead of sodium carbonate. The nitrocellulose is then washed with water and one last time with methanol before drying.

Hennig Brand - 15-11-2014 at 09:52

I am not sure why urea would be superior to sodium carbonate except that maybe traces of alkali left in the nitrocellulose could cause decomposition of the nitrocellulose in storage and trace amounts of urea left could act as a stabilizer. However, for colloided nitrocellulose powders (modern smokeless propellants), urea is apparently not a suitable stabilizer. From COPAE, "Urea is used in dynamite and in celluloid. It reacts with nitrous acid to produce nitrogen and carbon dioxide, and is unsuitable for use in smokeless powder because the gas bubbles destroy the homogeneity of the colloid and affect the burn rate. The small gas bubbles however commend it for use in celluloid, for they produce an appearance of whiteness and counteract the yellowing of age."

Ral123 - 15-11-2014 at 11:09

@Hennig Brand you said your material degraded for months. A sample made with WFNA/H2SO4 could burn very violent after more then an year and quite a time at elevated temperatures. It was only washed with tap water. Could it be that the highly nitrated is more stable?
I wont consider urea as a stabilizer because it releases water in it's reaction and water degrades NC. IIRC highly nitrated NC can detonate in a thick drinking straw. Witch I suppose makes it usable for base charge.

Hennig Brand - 15-11-2014 at 11:46

In most instances even after a couple years the material was still usable as propellant, but it was noticeably weaker than freshly made nitrocellulose. In a couple instances the material was extremely degraded and was very weak in comparison to freshly made nitrocellulose. Storing nitrocellulose in a sealed plastic bag, rather than letting it breath, seemed to greatly increased the rate of decomposition.

If you used mixed acid to produce your nitrocellulose it is unlikely that your product was that much more highly nitrated than mine. With a mixture of sulfuric and nitric acids the maximum level of nitration is around 13.4-13.5%N IIRC. Unless my estimates have been very inaccurate, I have produced nitrocellulose with a level of nitration of up to 13%N or so using ca. 91% sulfuric acid and a nitrate salt. Using nitric acid instead of a nitrate salt is supposed to produce a more stable product, however, because the product has less impurities.

Hennig Brand - 21-11-2014 at 12:27

I have been spending a little time looking into purification of nitrocellulose for long term storage stability. As was just discussed, putting less impurities into the reaction mixture, by using nitric acid instead of a nitrate salt, is probably the first step since it is likely easier than trying to remove the impurities post reaction. I have made several batches of microcrystalline cellulose, but have yet to nitrate any of it. If it is as easy to purify/stabilize as it is reported to be it may be the answer, at least for the hobbyist. I have also been experimenting a bit with cutting up, thrashing and poaching nitrocellulose made from cotton balls. A blender was used to do the thrashing. A set of kitchen shears was used to cut the NC batt into small chunks so that there would be no long pieces of fiber to wrap around the drive shaft and gag/burnout the blender. The blender was run on high speed and only for about 30 seconds, but it was obvious even from the short run time that it was thrashing the NC more than cutting it up. The thrashing did, however, seem to separate the fibers and fluff up the NC a lot as well as tear a lot of the fibers into shorter lengths (pulling the clumps apart between the fingers showed the shortened fibers). The NC also took on a much lighter color indicating that a lot of the junk from the drain cleaner acid and fertiliser grade nitrate had been released or shaken free. The next step was poaching; a short 20 minute boil was performed in a 2% sodium bicarbonate solution and then another 20 minute boil in clean water. All of these times are extremely short, and were only done as a quick test to judge the suitability of the process. Although, often times the greatest proportion of benefit comes from the first bit of time. During the thrashing and poaching about 0.34 grams of the about 15 grams of nitrocellulose was lost as fines.

From the document on military nitrocellulose specifications, attached below, it is obvious that nitrocellulose is cut/beat to a very fine form in industry (ca. <0.56mm fiber length). I could have easily cut the nitrocellulose up much finer in just a few minutes with scissors and the blender could have been run much longer, but I am sure that this is not the best way. I am still exploring the options, but there must be a motorized household implement, like a food processor maybe, that could perform an adequate job of nitrocellulose comminution (particle size reduction).

Nitrocellulose Previosly Washed.jpg - 252kB

Nitrocellulose Thrashed in Blender.jpg - 184kB

Dry Thrashed & Pulped Nitrocellulose.jpg - 419kB

Dry Thrashed & Pulped Nitrocellulose 2.jpg - 429kB

Attachment: Nitrocellulose Detailed Military Specifications MIL-DTL-244B.pdf (112kB)
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[Edited on 21-11-2014 by Hennig Brand]

Hennig Brand - 21-11-2014 at 13:05

Ran out of room.

Microcrystalline cellulose was made by hydrolyzing pure cotton cotton balls in a 5% HCl solution at the boiling point or just a little under. The cotton looked to have mostly fallen apart in less than 30 minutes, but the heating was maintained for a total of 2 hours. The dry product is very clumpy, but rubbing it between the fingers a bit shows that it is an extremely fine powder. I have yet to nitrate any of it, but it seems at this point like it might be the key to stabilized nitrocellulose for smokeless propellants for the hobbyist.

Hydrolyzing Cotton Balls to MCC.jpg - 461kB

Microcrystalline Cellulose in Filter.jpg - 307kB

Wet Microcrystalline Cellulose (MCC).jpg - 352kB

Dry Microcrystalline Cellulose (MCC).jpg - 436kB

[Edited on 21-11-2014 by Hennig Brand]

TGT - 21-11-2014 at 21:23

I have a large amount of Microcrystalline cellulose from ASA extraction when making Picric Acid. It was the only other additive in the aspirin tablet. Do you think this would work for nitration? It is as a total powder when wet and does not clump like wet cellulose. What do you think?

TGT

NeonPulse - 22-11-2014 at 01:45

All this talk about MCNC has got me pretty interested to try synthesizing some. Enough so that i purchased some pharmaceutical grade MCC. In the next week or so i will attempt to nitrate a small amount of it using a standard WFNA/sulfuric bath and will attempt to get it highly nitrated which should not be too difficult going by what i have read about the process involved from the Microcrystalline cellulose nitrate thread a few pages in from this one and the patent by a user here, Ordenblitz. although i wont be using it as a propellant since i have no firearms but i will attempt to detonate some in medium confinement and a with a reasonable cap. will see how it goes and i ll keep a nice record to post of my experiments with it.

Hennig Brand - 22-11-2014 at 06:55

If it is microcrystalline cellulose I imagine it would nitrate just fine.

I guess I didn't describe the homemade MCC from above correctly. It dried in clumps, but once broken up it stays as a powder, unless pressed. Yeah, it would be interesting to see the results of some tests with MCNC; it might just make a good base charge for detonators among other things. MCC can also be nitrated to a bit higher level of nitration, since there is the possibility of increasing the ratio of nitrate groups to cellulose monomers (more locations to add nitrate groups).

Here is an interesting document I found online giving an overview description of a, military specification, nitrocellulose production process.

Attachment: Nitrocellulose - Military Specification Production Process.pdf (202kB)
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[Edited on 23-11-2014 by Hennig Brand]

Cellulose Nitration Diagram & Spreadsheet

Hennig Brand - 19-1-2015 at 10:36

Here is an Excel spreadsheet for determining the approximate quantities of acids of various strengths required to obtain nitrocellulose of any strength (%N) desired. A couple of ideas were borrowed from the PETN Excel sheet that was posted many years ago and is still in circulation.

It is not completely automated and requires that a certain amount of iteration be performed by the user. The boxes in bright yellow are variables which can be changed. Changes are made until the post nitration mixture (end acid composition) matches up with the diagram for the %N chosen.

The nitration triangle diagram was taken from, "High Explosives and Propellants", by Fordham (pg.39).

It is very obvious that using 65% HNO3 and 91% H2SO4 is a very wasteful way to try and obtain NC of high percent nitrogen.

It may require changes, all input is welcome.

Attachment: Cellulose Nitration Diagram & Spreadsheet.xlsx (129kB)
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Attachment: Cellulose Nitration Diagram & Spreadsheet (compatibility mode).xls (143kB)
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[Edited on 20-1-2015 by Hennig Brand]

Rosco Bodine - 20-1-2015 at 06:15

Dear Lord, it's a one eyed, one horned, frying purple cotton eater

Hennig Brand - 20-1-2015 at 09:38

If one gets the nitration acid composition really wrong or fails to remove adequate heat it could definitely eat some cotton.

Do the numbers seem ok?

Laboratory of Liptakov - 22-1-2015 at 10:57

What's everybody here made? This is a some speciality of cook chef? I see, that photos are older, but I must be carefully what's the matter...

Hennig Brand - 22-1-2015 at 15:52

I assume that this is a troll, but I will answer anyway. Some chemists, even the amateur ones, would get angry if you compared their activity to cooking, but there are often a lot of similarities I find. I happened to be away from home, and got bored, and the kitchen implements used in the above photos were all I could gather together in order to hydrolyse some cotton. I think the results were the same as they would have been if I had been using laboratory grade glass and a laboratory grade hotplate.

Regular nitrocellulose is very difficult (especially for the amateur) to make storage stable because its physical form is such that complete removal of residual acidity and other impurities is very difficult. Microcrystalline nitrocellulose is in a form that is much easier to remove impurities from and make storage stable. Propellants can degrade quite quickly if not properly purified and stabilized; best case scenario the propellant losses performance, worst case scenario the propellant ignites and burns or explodes and causes death and destruction.

I am just evaporating the acetone from a fresh batch of double base propellant based on microcrystalline nitrocellulose, so maybe tomorrow I will test some of it.

NC

Laboratory of Liptakov - 23-1-2015 at 00:54

Henning, thank you. Microcrystalline cellulose, or very short fibers is an important raw material for the esterification. To ensure the best possible neutralization. Thus stability. Understood. I am curious about the tests.
... :cool:

...LL

NeonPulse - 23-1-2015 at 19:53

You are right about stabilizing the MCNC. the small batch i recently made had since decomposed quite dangerously. The container was full of the dreaded red gas. i thought it was washed and neutralized very well but i guess it was not good enough. Quite unnerving to find it in that condition. I immediatley disposed of it. it also was not stabilized in any way. Also the area it was stored gets pretty warm so that no doubt accelerated the decomposition.

MCNC/NG, 60/40, Double Base Propellant Testing

Hennig Brand - 24-1-2015 at 07:45

MCNC should be much easier to stabilize than regular NC. I have had MCNC and MCNC double base propellant in storage in plastic sandwich bags for a couple of months now and they show no signs of decomposition. After nitration the MCNC was well washed to remove nearly all residual acidity and then boiled in a 2% sodium bicarbonate solution for 10-15 minutes followed by another 10-15 minute boil in plain water. I have diphenylamine now, but I have yet to use any to stabilize a propellant.

I tested some homemade double base propellant this morning that was made from MCNC and NG. The performance was not as good as when regular NC was used and I am not exactly sure why. Double base propellant made with MCNC has much higher bulk density than DBP made with regular NC; 0.1g in the .22LR cartridge only filled it about 60% full whereas it would have been full to the brim if regular NC had been used. Higher density perhaps coupled with larger average particle size could have been the cause of lower performance. The other possibility is that MCC is more difficult to nitrate to a high percent nitrogen than cotton. The homemade MCNC DBP is still very serviceable propellant however.

The home made propellant is MCNC-NG, 60-40, and was made the same as the last propellant, based on regular NC, using acetone as the solvent. The home made propellant produced a muzzle velocity of 1166fps, while the commercial propellant produced a muzzle velocity of 1228fps (0.10g of propellant in both cases). The accuracy of the scales could have accounted for the difference in performance between the two, but there did also appear to be more dark colored fouling in the cartridge which held the homemade propellant (even a couple bits of unburned propellant could be seen). The MCNC propellant may require a stronger primer. At any rate the homemade propellant is very serviceable.

No stability testing has yet been done other than observing small samples held in regular storage.

Muzzle Velocity Commercial Propellant.jpg - 440kB

Muzzle Velocity Homemade Propellant.jpg - 421kB

[Edited on 24-1-2015 by Hennig Brand]

[Edited on 24-1-2015 by Hennig Brand]

roXefeller - 24-1-2015 at 12:48

What were the conditions during which the acetone solvent was evaporating? Is it possible it dried at a slow rate and you shot it too soon?

Bert - 25-1-2015 at 06:43

I am impressed. Do you even have time to show up at your day job?!

Have you looked at the information on "nitrometer" testing given in Naoum and Tenney Davis? I am curious as to the results from your microcrystaline NC.

Cellulose is an odd molecule, the length of chains is a major factor in physical behavior of lacquers and varnishes used for painting and coatings. Partial treatment as you have done to create MCC is use to alter viscosity of lacquers- When made with same solids content of NC & identical carrier solvent, the shorter the chains, the lower the viscosity. Allows a smaller droplet size in spray coating with same film build/volume of lacquer-

I would bet it has some effect on both nitration and thermal decomposition profile in propellants.

-------------

Did you disassemble and weigh propellant charge from one or more rounds of factory ammunition, then use the case(s) and projectile(s) to load the home made propellants? Followed by firing another (unmolested) round, or rounds from same lot of cartridges to establish factory round velocity?

If you are firing an "as factory assembled" round of .22 LR in comparison to your reloaded round, the mechanical differences induced to the reloaded round by your processing is a factor.

If I've guessed your test procedure correctly, try this again but treat both rounds EXACTLY the same way... Pull the bullet from the factory round and then put it back, the damages to bullet heel, loss of lubricant in handling and other small changes could account for 100 fps of velocity!

Also: unburnt grains of propellant usually equals too low operating pressure (damage to bullet, poor bore obturation (sealing)?)

Another factor in unburnt powder: A too large/non uniform grain size. If you have the capability, FLATTEN the powder. Just run the powder through a precisely aligned set of heated rollers? At least one dimension of each grain is then guaranteed to be the same, so burning time in that axis at least is uniform. A lot of ball powder is treated this way, giving a flattened ball profile to the grains- This improves uniformity of burning speed, regardless of non uniform grain weight (caused by variations in ball Dia.)

That simple little .22LR cartridge is a fiend to make uniformly, even in a professional factory setting. Witness the +100-500% difference in the cost of competition grade ammunition to cost of plinking grade .22 ammo! And the common practice of rifle teams, buying multiple cases of different lots of the same brand .22 ammo, testing, then reserving only the best lots for competition.

Larger centerfire rounds with jacketed bullets are more forgiving of tiny variations, if you have that capability. Perhaps even a muzzle loader of larger caliber would be more suitable to assess propellant differences, if it were possible to load exactly uniformly as far as depth of bullet seating, % of powder volume in area below bullet, bore condition, bullet hardness... All the minutiae of loading parameters.

Finally, what brand of .22 LR ammo are you using for the test case/primers? If it is a plinking/hunting grade, the less precise priming of such ammo can give a spread of velocities equal to what your single test showed here- In totally unaltered samples taken from the same lot/case/box!

[Edited on 25-1-2015 by Bert]

Hennig Brand - 25-1-2015 at 15:44

RoXefeller, good thinking, but after being cut into flakes the propellant was given a couple of days spread out at room temperature to get rid of nearly all the acetone.

Bert, thanks for the very informative reply.

I have read about nitrometers a few times, but thought at the time that they were complicated and specialized. Perhaps I should give them another look.

You are correct, the ammo is cheap plinking ammo called American Eagle, put out by Federal. I have tested many rounds and it is common for every second or third round to be as much as 20fps, or even higher in a couple cases, than the average. The way I am pulling the bullets is horrible; the bullet is wrapped in multiple layers of paper and then griped with vise grips and then pried and pulled out. I have had to throw out some bullets because they got significantly damaged while trying to remove them from the casings.

"Did you disassemble and weigh propellant charge from one or more rounds of factory ammunition, then use the case(s) and projectile(s) to load the home made propellants? Followed by firing another (unmolested) round, or rounds from same lot of cartridges to establish factory round velocity?"

Yes, that is exactly what was done. I have weighed half a dozen or more from the same box and the load was reasonably consistent, at least as far I could tell with the accuracy of my scales. The commercial load weighed between 0.09 to 0.10g in those measured. Obviously the accuracy of the scales are a real problem here. I did just get a set of scales which will give me another decimal place though. Also, your suggestion to pull the bullet from the factory load to be tested and weigh the powder before reseating the bullet is a good one. This would help ensure that the powder load weight was the same for both the commercial and homemade tests and if done carefully help ensure that the bullets and casings were in the same condition before the test.

I may look into a set of rollers. Seems like a cheap and easy way to ensure at least one dimension of the propellant flakes are the same, as you suggest.

The .22LR was chosen because it was cheap and readily available to test and thought to be safer than performing tests with a larger caliber rifle. You are right though, it is much more difficult to get accurate test results with the .22LR for many reasons. I imagine that everything, including the primer load, has lower tolerances in a .22LR plinker than in a decent center fire rifle round. Larger rifle rounds really would absorb much better small differences in power weight and other loading specifics (percent differences are much smaller for same inaccuracies).

[Edited on 25-1-2015 by Hennig Brand]

roXefeller - 25-1-2015 at 18:09

Don't know your personal collection, but revolvers can be overloaded and work pretty well. I've fired 44mag out my ruger filled to 100% with ball powder. But you could also down-load. If you had either a 44mag or 357mag, you could look up the grain loads for the 44spl or 38spl and load for those. You would have a normal cartridge, but your firearm would have strength margin in case the load was stronger than anticipated.

Another thought is the ballistic modifiers used in the NC based propellants. It makes the burning rate of the propellant smoother, so it doesn't burn powder too fast at high pressures.

Either way, 1100 or 1200 fps, you're correct, it is a very serviceable load. Too bad single base rifle propellant would be crazy to form.

MCNC/NG, 60/40, Double Base Propellant Testing in 30-06 Rifle

Hennig Brand - 30-1-2015 at 08:27

This morning I dug out a 30-06 Winchester rifle and some old cartridges to do some further propellant testing. The propellant used was from the same batch as was used in the last .22LR test. I had an assortment of old 30-06 rounds, but several of them looked to be the same. The bullets were carefully removed from two rounds using the method described here:

https://www.youtube.com/watch?v=XVaE_LKmjPc

Basically an empty casing of the same type was slid over the bullet and rotated around with some hand pressure to loosen the bullet and then the bullet was pulled out by hand.

The bullets and powder loads were weighed. One was reloaded with the full commercial load and another was reloaded with homemade double base, 60-40, made with MCNC. The bullets weighed ca. 150 gr (ca. 9.7g) and the loads of commercial propellant were ca. 45 gr (ca. 2.9g). On reviewing loading data pages it looked as though single base tubular propellants were often used to load 30-06 shells. Since the homemade propellant was 60-40 double base, flake propellant, it was decided that a lighter load should be tried first. The load of homemade propellant weighed out was 2.5g, but only 2.0g was used since because of the lower bulk density, relative to the commercial tubular propellant, 2.0g filled the casing up to the neck.

I am glad I didn't use a heavier homemade powder load, the 2.0g of homemade propellant produced a muzzle velocity just slightly less than the 2.9g of commercial propellant (2631fps versus 2647fps).

Bullet weights: 9.7g
Commercial propellant load: 2.9g tubular SP (single base?)
Homemade propellant load: 2.0g double base, 60-40, flake (based on MCNC)

Muzzle velocity commercial propellant: 2647fps
Muzzle velocity homemade propellant: 2631fps

Commercial Tubular Propellant.jpg - 245kB

Commercial Propellant Muzzle Velocity.jpg - 341kB

Homemade Propellant Muzzle Velocity.jpg - 337kB

[Edited on 30-1-2015 by Hennig Brand]

Dornier 335A - 30-1-2015 at 08:50

Impressive results! I suppose the primer was stronger this time and/or the heavier bullet helped the propellant to burn more complete.

Have you estimated the nitrogen content of your MCNC?

Bert - 30-1-2015 at 09:02

You are fairly new to reloading. The test you described made my hair stand up, I hope you were not HOLDING the rifle!

Extruded powders used in medium bore bottle necked cartridges like the 30-06 are usually single base, as you guessed. Your 60:40 powder is probably a LOT hotter burning.

Your uncoated grains are likely degressive burning, the perforated tube grains would be close to neutral burning, and probably coated with deterrents to effectively give a progressive burn.

I would bet your propellant is producing far higher than design pressure for 30-06 early in the burn, please post clear pictures of the cartridge heads of the factory and experimental round? How do the primers look, is the home made propellant one more flattened! Did primer cup metal flow into firing pin hole, pick up all the little details of bolt face more so than factory round? Did case head flow brass into the gun's extractor cut out, was it harder to extract experimental round?

If you have a rifle that can be sacrificed to science, put a strain gage on the barrel and are firing from a protected, remote location- Something more might be learned. If not, I'd stop.

I will try to assemble more information on how commercial powders are tested.

Interior ballistics

[Edited on 30-1-2015 by Bert]

Hennig Brand - 30-1-2015 at 09:32

If it would make you feel better I could tell you that I wasn't holding the rifle, but I would be lying.

The empty casings look basically identical. The casing for the homemade propellant did not seem any more difficult to remove after firing. Primers look identical. I am indeed fairly new to reloading, but I read enough beforehand to know that I was taking a risk.

The casing on the right in the pictures is the casing which held the homemade propellant.

[Edited on 30-1-2015 by Hennig Brand]

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