Sciencemadness Discussion Board

Using a .22 round or centerfire as an initiatory?

crazedguy - 13-12-2012 at 06:37

The primer has lead azide in it, and I've read about some body using a torch to detonate the primary in it. But on mythbusters they use electricity to detonate them.
So the question is could you cast something like ETN into the .22 casing and have easy cheap detonators?

hissingnoise - 13-12-2012 at 07:01

Quote:
So the question is could you cast something like ETN into the .22 casing and have easy cheap detonators?

Not if you value your eyes and fingers ─ ETN is dangerously sensitive when heated!
And the small size of .22 cartridges makes them of little use, overall . . .




Motherload - 13-12-2012 at 07:06

I am not going to say ... "If it were that easy everyone would do it".
But rather tell you from what I understand .... The amount of Azide in the case is minuscule.
It's enough to generate a spark for a flammable propellant but not enough to detonate ETN.
I tried making caps with PETN and magnum rifle primers..
Not getting consistant detonation.

crazedguy - 13-12-2012 at 07:16

Auto ignition for lead azide is 330C ETN melting point is 61C.
Motherload gave me the answer i was looking for though.
But could you extract the lead azide from a few using say acetone and make a cap from that fairily easy?

Ral123 - 13-12-2012 at 07:37

What's wrong with a thick straw with AP and recrystalized, stabilised with urea ETN? If the straw is warped with Al foil where the AP is, that would provide additional confinement. cheap-reliable-convenient what more? Lead azide has flame sensitivety issues you know...

crazedguy - 13-12-2012 at 17:04

Using a case as a detonator would require zero synthesizing of a primary and be fairly mass producible, so could be of quite a bit of use if it actually worked.

Farnsworth - 13-12-2012 at 21:12

The main ingredient in most percussion primers is actually lead styphnate. A few contain minute amounts of azide, but so little as to be of fairly unusable consequence.

That being said, lead styphnate itself can be used as a primary effectively. It's VoD and brisance are fairly comparable to lead azide, and the difference can be made up by slightly increasing the quantity and confinement. A couple grams in good confinement with 250mg or so of ETN pressed under it makes for robust and reliable initiations for most energetics. Orders of magnitude safer to handle than TATP or HTMD as well. Just beware of heat and static, as styphnate is very spark sensitive.

Ral123 - 13-12-2012 at 23:16

Yes because straws of AP are so expensive. For me reliability is priceless and these 0.22 cartridges would be junk. May be the primer cap is a good detonator for only one secondary-lead picrate :D

The_Davster - 14-12-2012 at 02:47

Quote: Originally posted by Farnsworth  
The main ingredient in most percussion primers is actually lead styphnate. A few contain minute amounts of azide, but so little as to be of fairly unusable consequence.

That being said, lead styphnate itself can be used as a primary effectively. It's VoD and brisance are fairly comparable to lead azide, and the difference can be made up by slightly increasing the quantity and confinement. A couple grams in good confinement with 250mg or so of ETN pressed under it makes for robust and reliable initiations for most energetics. Orders of magnitude safer to handle than TATP or HTMD as well. Just beware of heat and static, as styphnate is very spark sensitive.


Lead azide and lead styphnate are nowhere near comparable in terms of initiating ability.