Feeding/Extraction issues

[Stan_TheGunNut]

I have a number of AR's, but this is the first one that has caused me issues and I'd appreciate some help diagnosing the issue. The 14 pages of search results on this site and Google failed me.

I have a new BCM 12.5" factory upper that I bought new from BCM with a BCM BCG and charging handle. I paired it with one of my registered lowers and fired a couple of magazines through it today with no issues. Then suddenly, I began to experience a failure to extract followed by a double feed (empty case on top tried to chamber with the new round). This happened multiple times in a row. I would clear the rifle, chamber another round, and the same failure. Total rounds on the gun are <100 and rifle was lubed. No obvious signs of damage or problems with magazines.

The rifle was set up with the BCM upper and BCG on a PSA lower with an H2 buffer and standard trigger. Ammo being used was PMC Bronze 223 with a Gen 1 Pmag. After the problems started, I decided to swap mags and try and different ammo so I shot the rifle with a Lancer L5AWM and some Independence 5.56 ammo that was in my range bag. I got the same results, a failure to extract/eject followed by the rifle trying to chamber the spent casing along with a fresh cartridge. All of these combinations ran fine in a BCM 14.5 upper that I had with me. Ultimately, I borrowed a carbine buffer and spring from a friends well used rifle, and was able to fire the remaining 16ish rounds of Independence out of the 12.5" upper with no issues. Once home, I field stripped and visually checked things out and saw no obvious problems. Extractor tension seems good (and it's a new BCG).

I'm off tomorrow and may go back to the range to do some troubleshooting and it would be nice to have a plan prior to heading out. My questions are do any of you see any problems with my setup and if so, what would you suggest I change? I'll probably take a few different weight buffers, some ammo from a variety of manufacturers, and some other magazines. I generally only shoot brass cased ammo and the purpose of the rifle is primarily plinking. The rifle did prove very accurate.

Thanks.

[titsonritz]

Try better ammo.

[wildcard600]

So the bolt is extracting the case but not ejecting it ? If that is the case check to see if the extractor has the o-ring installed as it may be too much tension on the extractor and overpowering the ejector. Some of my BCM's came with the o-ring pre-installed.

[Stan_TheGunNut]

So the bolt is extracting the case but not ejecting it ? If that is the case check to see if the extractor has the o-ring installed as it may be too much tension on the extractor and overpowering the ejector. Some of my BCM's came with the o-ring pre-installed.

Thank you. No rubber o-ring was installed.

[Vegasshooter]

Ammo. PMC is always mentioned in threads that have problems. Step up to Federal American Eagle and I bet the issue disappears

[wildcard600]

Ammo. PMC is always mentioned in threads that have problems. Step up to Federal American Eagle and I bet the issue disappears

OP also reported issues with Independence 5.56 which is known to be hot, sometimes dangerously hot. Does not seem like an ammo issue to me.

You may want to try that BCG in another upper and see if the problem follows the bolt. If that is the case your ejector may be at fault. If so i'm sure BCM will fix you up.

[TacticalMark]

I agree with wildcard and bring another BCG. Try running a H buffer, H2 might be too much. Did it lock back on empty with the H2?

[Stan_TheGunNut]

Thanks for the suggestions. I'll be trying a variety of ammo tomorrow. I've packed up some more PMC Bronze, PMC Xtac, Wolf Gold, Federal XM193 and 855, and a couple of flavors of Hornady and Black Hills. I'm also taking some other buffers from standard carbine up to H3 (the bolt did lock back on empty with an H2). Lastly I'll be taking a couple of other BCG's to try. Short of swapping out buffer springs, which I don't have any non standard ones, this is about all that is readily changed out on the rifle. Hopefully I'll narrow down the issue. Who knows, it may have just needed to have a few rounds put through it.

Again, thanks to all for the suggestions.

Edit: I'll take another couple of rifles and try the BCG in them to see if the problem follows.

[NYH1]

I had a similar situation with a Centurion Arms BCG. It wouldn't eject spent cases and would try to load a new round in it's place. It also wouldn't lock the BCG back on the last round either. We tried different buffers and buffer springs, none worked.

Ended up swapping the BCG out with a new one that's been perfect ever since. Centurion to care of it without question. If you can't get it figured out without much more hassle, I'm sure BCM will do the same.

Good luck, NYH1.

[Iraqgunz]

A double feed, is two live rounds feeding into the chamber at the same time. You are experiencing some kind of extraction or ejection issue based upon your post.

A BCM 12.5" should run fine with an H2 buffer.