[boing]

While I was at the range yesterday I noticed some brass on the ground that didn't look right. It was PMP .223 brass, and on every one the extractor rim was nearly sheared off by the extractor. Many cases had that portion of the rim completely missing. They were all in the same general area, away from the shooting bench, as if they had ejected properly from a rifle.

What would cause this? Is there a gun out there that's known for this? Mechanical problem? Is PMP brass typically soft?

[TODD3465]

Those could have been fired in an AR Pistol. I've seen this happen with the 7" or 7-1/2" shorty ones. Too much gas blowing back too soon trying to unlock the bolt BEFORE the chamber pressure goes down. :what:

[DougB]

I've shot a lot of PMP through a couple of ARs and a Mini-14 and not experienced this. I don't think it's a problem with the PMP cases.

Doug

[Redlg155]

What did the cases look like otherwise?

A dirty/rough chamber could also cause these problems. Combine that with a chamber that is slightly out of spec and you could very well see torn rims.

Good SHooting
Red

[boing]

They had been on the ground for awhile, but I didn't notice any excessive scratches or other deformities. I looked for deep ejector marks to go along with the evident violent extraction cycle, but they looked nomal to me.

[dickwholliday]

i don't know what caused it but a buddy and i were shooting his Wilson AR the other day and had a bunch of the same thing you're describing....the rim would tear off on one side and the fired round would stay in the chamber...the new ammo was PMP....we fired my good ole reloads of Uncle Sams brass and the problem went away....i think this is a brass problem...maybe too brittle or something......either way, i would stay away from the PMP....DICK

[Watch-Six]

DPMS warns against using PMP in their AR rilfes. They say that the brass is soft. I have had a couple of jams with it in a DPMS. It has worked fine in my other ARs. It is probably best avoided. Watch-Six

[TODD3465]

Maybe they ought to name it PIMP instead of PMP?:D

[Kharn]

My Oly AR was having some problems with PMP when we hit the range last, after about 100-150 rounds it started having FTEs with the extractor jumping off the rim (and pulling the rim back to about 20-30 degrees from the face of the cartridge). Upon cleaning the rifle that evening, I noticed the little rubber thingie was missing from inside the extractor spring, so that probably caused the problem. I'll be getting a replacement rubber thing and a few D-rings with my next brownells order.

Kharn