Strange marks on 9MM blazer brass -- range pickup

[Conditor22]

Any idea what caused these Strange marks on 9MM blazer brass -- range pickup.

We also found a bunch of 40SW brass, they couldn't have shot these in the 40 SW?

https://i.imgur.com/YFuJ76P.jpg

[Pipefitter]

Kinda reminds me of 308 brass shot in a fluted chamber Cetme, maybe a full auto something?

[tomme boy]

Shot out of a MP5

[bld451]

Some pistols have fluted chambers similar to the HK 91&93. Some examples would be a P7 or an MP5. There are others, I'm sure. Inspect it like any other. I load them. They are fine unlike the rifle brass from fluted chambers. I don't find much brass ejected from HK rifles that I would use. Those systems are hard on brass. Not so much with the pistols, I have found. It is to assist with extraction.

[Idz]

HK delayed blowback guns used a fluted chamber to fix hard extraction problems. Some people reload them but some say never reload them.

[EMR]

^agree with them.

Looks like the brass out of my P7M8

[dansedgli]

The old STI apiero's had a chamber like that too.

[kevin c]

I've reloaded 9mm brass that looked like that. AFAIK, it cleaned up, sized, reloaded and shot fine (900 fps out of a Glock with a 148 gr slug loaded over a fast powder).

I too was told that fluted chambers were the cause.

[rcslotcar]

That is exactly the same as brass fired from my p7 psp. Looks ulgy but after cleaned with pins it reloads fine.

[Rigsby]

Yups,

Looks like mine shot from a P7-M13

[beagle]

Loaded a bunch like that for "shoot and scoot" (no brass picked up) ammo. Never had any problems./beagle

[Mr_Sheesh]

Used to get to shoot an HK 91 (308) a lot; Same sort of marks, and if you don't get the brass buffer it dings the brass badly. Buffer's worth it. I never had problems with reloading it, just clean it well to prevent scratching. That particular rifle shot rather well, and at night almost no sparks from the muzzle (blc(2) powder is fairly fast. 180 Gr SpSP's)

[Petrol & Powder]

That is exactly the same as brass fired from my p7 psp. Looks ulgy but after cleaned with pins it reloads fine.
/\ Ditto /\

Fired in a P7 and I've been reloading similar brass fired from a P7 for years.