What are these lines?

[RacerX]

I’ve noticed these lines on 9mm cases from reloads bought as components (unrelated issues). Any idea what they are from? They appear to be machine marks, but in a really bad spot (certain that’s not the case here though).

Thoughts?

 

[Frack N Cylons]

Are youu talking about the cannelure or the little Glock smile at the bottom?

The cannelure is to help prevent bullet setback.

 

[Chdamn]

Are youu talking about the cannelure or the little Glock smile at the bottom?

The cannelure is to help prevent bullet setback.

I believe he’s talking about the cannelure (new word I just always called it a roll crimp).

For the OP as stated it prevents bullet setback. Basically it makes a little shelf inside that prevents the bullet from being accidentally crammed back into the cartridge.

 

[RacerX]

Thanks. That’s what it is! I always leaned towards caution and pitched them. I’ll hold onto them moving forward.

 

[Frack N Cylons]

Yea they’re good to go. The little shelf the cannelure creates will be pretty much ironed out on the inside after the first shot.