I know that my dad has something like that for crimping coax cables. It crimps uniformly around the circumference leaving behind little impressions. I
know they do make a crimper specifically for crimping blasting caps.
I think I recall it being stated in the comments that a lathe was used. You can buy these casings as they are used for making sealed probes. Lookup
thermowells and sensor casings/housing, or closed end tubes.
I made the mistake of confusing videos, as I didn't watch the link. I have watched it before, but mistook the crimper used for another video. This,
again, seems to be something he likely turned on a lathe, himself.