I assume this is a factory applied crimp, and I have seen them before. My question is why would it be so far down on the case? Cannot imagine a 38 Special with a bullet that long, and if it were to prevent setback it would not stop the bullet until it was already inside the case. I know this is a beginner level question, but relatively speaking I still am.
Also, I searched the Internets but cannot find a comprehensive discussion of crimps. Everything seems to be roll vs. taper for reloading. Anyone have a link that covers the ones you see on military and commercial ammo?