05-02-2020, 08:53 PM
BluntForceTrauma Wrote:Got detailed pix of the extractors and the bolt? If you don't mind, I'm studying Grendel extractors to re-design them to make them stronger.
It's a PSA BCG. FWIW, I'm running this one in a Bravo Company upper (their barrel connection zone is amongst the tightest of any upper you can get, for a firm fit), that had been lapped, and with an Alexander Arm's BBL. Gun cycles and operates fine, brass normally comes out just fine, with no indicator that headspace is out of spec (i.e. brass stretch is the same as typical), and the brass fell out of the chamber just by tipping up the barrel, so not a rough chamber apparently.
The extractor was Stamped 7-2 on the inside, and appears 100% identical to the Black Rifle Arm's co replacement extractor I just put in, including the 7-2 marking. As far as I know it's the original PSA extractor, but in any event it's apparently the same extractor that BRA uses. It ripped off the claw. The new BRA replacement extractor has the inside corners of the claw slightly relieved and radius-ed (as correct for Grendel); and I haven't test fired that yet.
So far, while I do love Grendel - the extractor experience has not been good for me. I keep round-count records on each gun. In 60,000 rounds of 5.56 (several rifles), I've broken 1 extractor. In 2,500 rounds of Grendel, I've already broken 2. Which is a ratio of Grendel breaking about 50X higher than my 5.56 extractors do.