Took it out of the box and ran a dry patch through the bore.The rest looked to have enough lube.120 rounds without a hitch.Couple inches low at a hundred,other than that it was perfect.
  On the other hand I shot my carbon 15 once.Yep once before it ripped the rim of a South African round and broke the extractor.I was bragging on it because it ran over a thousand rounds without a problem.This was early 80's PMC.nothing else has worked.Back to PO.
  Could this gun be unlocking to soon and ripping the brass because pressure is sill making the case cling to the wall?

Dude....you need to clarify this post.......