Trying to find the cause of my FTE/FTF

[thekman24]

Hello all,

Ive had a couple issues with my AR during a couple 3 gun competitions. Ive had a failure to eject/extract along with a double feed happen to me twice on two different occasions. My lower receiver is not milled out for the M4 feed ramps my barrel has so I was wondering if that was the issue. Take a look at my picture. These are the rounds that came out of my rifle, one from each occasion. Any thoughts?

[assaulter]

Could be the gas rings or the carrier key. Slowly feed a few rounds and see if the tip is hanging up at the feed ramp. I doubt it is though.

[kurtm]

Extractor spring!!

[thekman24]

Ok.. well thats a place to start. Either gas rings, carrier key or extractor spring. How would the gas rings or carrier key do something like that though? These are semi-isolated incidences too. Once in every 500 rounds or so. It happened once last summer and once this spring and I shoot a decent amount. I decided to not use that upper/carrier combo any more for 3 gun. I bought a DPMS 3G1 upper so hopefully that issue goes away!

[gerritm]

We had the exact same looking brass in my son's Olympic Arms lower. Paritally solved it with using steel mags instead on P-Mags. The magwell was slightly out of spec and was too large. It was not holding the magazine feed lips tight and on occasion it would double feed. Especially when you first load the mags and bump the bottom to make sure they were seated. It would pop 2 shells out and cause a double feed and the shell cases looked exactly like that.

Tried putting a heavier buffer to slow down the action and again it helped but would still happen every 100 rounds or so. Tore our hair out because it was so random and could be in the middle of a run or when he dropped to go prone. Had many expereienced AR shooters and builders look at it and no one could figure it out. Had a thread here and tried all the suggestions, but none worked. Almost all said they thought it was a mag problem.

Solved the problem by replacing the lower with a Spikes Tactical lower and have not had any problems since. Same bcg, gas block, barrel, and all parts on the upper. Uses any mags you put in it including the 60 round Surefire and P-mags.

gerritm

[thekman24]

I was thinking it could be a magazine issue too. Next time it happens (if it does), I make sure to make note of the magazine that it happened with. Ill try a different mag and if it still happens with my new upper, it would have to be the lower.

[StealthyBlagga]

1) Could be magazines: Start with new GI magazines to confirm they are not causing the problem - cheap and easy.

2) Could be a gas leak/problem: Check for sufficient gas: place one round in a magazine, load it and fire. If bolt locks open consistently, then you have enough gas.

3) Could be a stuck/weak ejector: Lubricate the ejector (drench in oil, then push in and out several times, then wipe up excess and repeat a few more times). Confirm it moves freely and with sufficient force. If in doubt, remove the ejector, clean out its hole, and replace the ejector spring.

4) Could be a weak extractor: Particulary a problem with carbine gas systems. Remove and clean your extractor and its pocket. Inspect the extractor claw for damage. Consider an extra power extractor spring.

[thekman24]

Thanks for all the advice. Ill definitely look more into this if (when) it happens again.