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.

[Hero]

Thank you. No rubber o-ring was installed.

Just to see, try installing an o-ring and repeating your function test. I'm thinking not enough extractor tension rather than too much. The extractor is letting go of the case rim prior to the case being fully extracted, preventing it from being ejected, so it just kind of flops out into the chamber/feeding area. The next round tries to load but the spent case is in the way.

I'm no expert, but I've remedied two uppers doing exactly as you describe by installing the BCM extractor upgrade kit (spring, black insert, o-ring). I've read this is a "Band-aid" as opposed to a "fix", but it turned those uppers into 100% for me.

[georgeib]

Just to see, try installing an o-ring and repeating your function test. I'm thinking not enough extractor tension rather than too much. The extractor is letting go of the case rim prior to the case being fully extracted, preventing it from being ejected, so it just kind of flops out into the chamber/feeding area. The next round tries to load but the spent case is in the way.

I'm no expert, but I've remedied two uppers doing exactly as you describe by installing the BCM extractor upgrade kit (spring, black insert, o-ring). I've read this is a "Band-aid" as opposed to a "fix", but it turned those uppers into 100% for me.
This.

My guess is that the rifle worked at first because your chamber was clean. But as it got dirtier, extractor tension became insufficient. I bet either a chamber cleaning, or the extractor o-ring will remedy the problem.

[MistWolf]

Replace the extractor spring with the current Colt extractor spring and no O ring. The O ring was never meant to be a permanent fix.

Ammo won't cause this malfunction as described unless the case rim diameter is too small

[Iraqgunz]

Exactly. Get a new spring. I have used the BCM enhanced spring, the Colt and the Sprinco spring and have had zero issues.


Replace the extractor spring with the current Colt extractor spring and no O ring. The O ring was never meant to be a permanent fix.

Ammo won't cause this malfunction as described unless the case rim diameter is too small

[Stan_TheGunNut]

Thanks for all the feedback. I took the rifle back to the range today with some buffers of various weights, a spare BCG, and a variety of ammo. I was unable to duplicate the issue I had yesterday using the same ammo, and other brands, and different magazines. Today in addition to the PMC Bronze and Independence, I fired some XTAC, PPU, and American Eagle 5.56 and 223. I fired it enough to get it warm, let it cool, fired some more, and it ran great. No parts were changed from yesterday. Since it's a new upper, I'm just going to write it off to needing a bit of a break in. The rifle is a bit dirty now. I'll go back to the range later this week and give it another run. If it has issues again, I'll try some of the suggestions here.

I appreciate everyone's help and suggestions.

[MistWolf]

Don't worry, Stan. The problem will return later. That's the trouble with a failing spring. You can clean and lube the rifle and the spring will start doing its job again and everything will work fine. Until the spring fatigues a little more and the problem returns. This cycle will repeat itself over and over enough times to have you thinking "but every time I have this problem, cleaning and lubing fixed it, do it just needs another cleaning and lubing." The intervals between "cleaning and lubing will grow shorter and shorter until, out of desperation, you finally replace the spring. I went through this on two different ARs before I learned my lesson. I ordered a bunch of extractor springs from Brownell's and replaced every extractor spring on every bolt.

So, you can replace your spring now and save yourself time, ammo and aggravation, or you can just press on and see what happens :)

[wildcard600]

Don't worry, Stan. The problem will return later. That's the trouble with a failing spring. You can clean and lube the rifle and the spring will start doing its job again and everything will work fine. Until the spring fatigues a little more and the problem returns. This cycle will repeat itself over and over enough times to have you thinking "but every time I have this problem, cleaning and lubing fixed it, do it just needs another cleaning and lubing." The intervals between "cleaning and lubing will grow shorter and shorter until, out of desperation, you finally replace the spring. I went through this on two different ARs before I learned my lesson. I ordered a bunch of extractor springs from Brownell's and replaced every extractor spring on every bolt.

So, you can replace your spring now and save yourself time, ammo and aggravation, or you can just press on and see what happens :)

Since its a new BCG I think the OP would be better off getting with BCM if the problem persists instead of throwing springs at the issue which may or may not be the problem.

[MistWolf]

There was a spate of malfunctions that were the same as this one. In every case, the reported fix was replacing the extractor spring or replacing the spring and the extractor. I think I've got a post somewhere that explains why this is caused by the extractor losing control of the empty case.

Replacing the extractor spring is cheap and easy. I got the Colt springs for about $6 each from Brownell's

[wildcard600]

There was a spate of malfunctions that were the same as this one. In every case, the reported fix was replacing the extractor spring or replacing the spring and the extractor. I think I've got a post somewhere that explains why this is caused by the extractor losing control of the empty case.

Replacing the extractor spring is cheap and easy. I got the Colt springs for about $6 each from Brownell's

With new BCM carrier groups ?

[MistWolf]

Yes, sir

[Iraqgunz]

Agreed 100%. I had a BCG that suffered an issue within a few hundred rounds. Bad ejector spring was the issue.


Don't worry, Stan. The problem will return later. That's the trouble with a failing spring. You can clean and lube the rifle and the spring will start doing its job again and everything will work fine. Until the spring fatigues a little more and the problem returns. This cycle will repeat itself over and over enough times to have you thinking "but every time I have this problem, cleaning and lubing fixed it, do it just needs another cleaning and lubing." The intervals between "cleaning and lubing will grow shorter and shorter until, out of desperation, you finally replace the spring. I went through this on two different ARs before I learned my lesson. I ordered a bunch of extractor springs from Brownell's and replaced every extractor spring on every bolt.

So, you can replace your spring now and save yourself time, ammo and aggravation, or you can just press on and see what happens :)

[Cane55]

Don't BCM BCG's come with the BCM extra power extractor spring? Or no? I was under the impression all BCM BCG's came with the extra power springs standard.

[georgeib]

Don't BCM BCG's come with the BCM extra power extractor spring? Or no? I was under the impression all BCM BCG's came with the extra power springs standard.
Mine did not. It only came with a "standard" spring with insert installed and the o-ring not installed, but provided in a separate bubble of the plastic bag the bcg came in. When I replaced the spring with one that came in a 3 pack from BCM, the replacement was longer and to my eye beefier than the one that came in the BCG.

[Hero]

Mine did not. It only came with a "standard" spring with insert installed and the o-ring not installed, but provided in a separate bubble of the plastic bag the bcg came in. When I replaced the spring with one that came in a 3 pack from BCM, the replacement was longer and to my eye beefier than the one that came in the BCG.

+1

I had this extraction issue with a new BCM upper with new BCM BCG. I installed the BCM extractor upgrade kit (spring, insert, o-ring) in the bolt which fixed the problem. The extractor spring that came out of the new BCM bolt was about a coil shorter than the extractor spring that came with the upgrade kit.

[Cane55]

+1

I had this extraction issue with a new BCM upper with new BCM BCG. I installed the BCM extractor upgrade kit (spring, insert, o-ring) in the bolt which fixed the problem. The extractor spring that came out of the new BCM bolt was about a coil shorter than the extractor spring that came with the upgrade kit.

Yeah your both right. I just checked my BCM upper and realized it came with a regular extractor. I'm gonna upgrade to the enhanced extractor. The enhanced extractor works fantastic.

[wildcard600]

I just pulled a couple of my bolts apart and checked the extractor springs, they look the same as the replacements BCM sells by themselves to me. Is there any definitive proof or is this conjecture al la TOS ?

[Cane55]

Every bolt I've installed the BCM extractor upgrade on has functioned 100% perfectly, even with Tula and Wolf ammunition (I literally have not had a single malfunction with Tula or Wolf ammo after thousands of rounds). IMO its one of the best - if not the best - reliability upgrades there is for an AR and for only $4 it's a no brainier. Besides adding the enhanced extraction improvement it also should last a very long time since it's made out of chrome silicone. Another outstanding BCM product.