This seems strange.
There shouldn't be an oring anywhere near the cam pin.
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Like I said, just curious. I don't run them. Don't think it is needed. If it is that tight, and I hate to say this, but run it more.
What is the deal with the o-ring on the cam pin? I have never seen or heard of that. The only thing AAC on my 300 is the barrel. Keep us informed, as I am now highly interested.
No marking on bolt. O ring on extractor.
The o ring on the cam pin was very odd. I wish I got a picture, but if you look at the cam pin as a "T" the o ring is a very thin circular piece of rubber right underneath the top of the T. Best I can describe it.
I am going to remove the o ring then test. If there are still issues I will swap extractors. Still more and then swap bolts.
Never seen anything like what you describe on the cam pin. Thinking through the cycling operation, I can't think of any reason for it to be there or why anyone might think to put it there. At best it would do nothing, at worst it would add drag and eventually introduce debris from it's deterioration into the weapon.
Is the ammo factory? If so from whom and what weight projectile?
From ACC's website - the 9" and 12.5" AAC 300BLK Uppers are designed for use with a carbine receiver extension, standard GI Buffer Spring, and an H2 Buffer.
The 9" AAC is designed to run with an H2 buffer.
From AAC's website:
IMPORTANT NOTES:
-The 9" and 12.5" AAC 300BLK Uppers are designed for use with a carbine receiver extension, standard GI Buffer Spring, and an H2 Buffer.
I would be asking your buddy to show me how he cleaned and reassembled his BCG, especially with the o-ring on the cam pin. A little friendly education works wonders some times.
Get him to join this forum!
I had a similar problem once and it turned out to be my gas block coming loose. It worked great then got worse and worse until it wouldn't extract at all.
I had a similar problem with a Noveske barrel I used for an 8" build. Bottom line was the O-ring on the extractor -seemed- to be the difference (same as you one BCG worked the other didn't) but ultimately the buffer was the issue. I wish I could remember my exact combination of problems and possible solutions.
What's the chances he tore the BCG down for a cleaning, removed the O ring from the extractor, and then as it was reassembled he didnt remember where the o ring came from and managed to shove it onto the cam pin? I wish I had one sitting around I would give it a try for fun.
I never heard of an o-ring on a cam pin.