View Full Version : Fail To Feed/Double Feed? Magazine Problem or Something Else?
OK thought it was my lightweight carrier (I know..)
When firing, it will fire two rounds then mis feed. The bolt will jam into the cartridge midsection denting it pretty badly.
but then dropped in a Stag NiB full weight FA standard BCG and it still did it
and getting this when cycling the charging handle to strip rounds - see pics
could it just be some bad magazines/ weak mag springs?
I was using some very high quality 20 round OKay Ind. black teflon coated mags and did not even consider something being wrong with those.
they don't have the anti-tilt followers though...
I stripped rounds from some 30s from C Products that had no issues. Will have to try those in live fire.
Any help is appreciated. Thanks
524005240152402
When you changed bcg, you mean including a different bolt?
What exactly do you see? A fresh round that was overridden by the bolt, where is the empty?
Do you have 1 or 2 fresh rounds stipped from the mag?
You are getting this malfunction even when hand cycling the bolt?
Do other mags work flawlessly?
Is this a new build, has the upper and/or lower been reliable in the past? Factory gun?
When you changed bcg, you mean including a different bolt?
What exactly do you see? A fresh round that was overridden by the bolt, where is the empty?
Do you have 1 or 2 fresh rounds stipped from the mag?
You are getting this malfunction even when hand cycling the bolt?
Do other mags work flawlessly?
Is this a new build, has the upper and/or lower been reliable in the past? Factory gun?
The upper is a 2A billet, 2A rail, Spikes 11.5, 2a Ti gas block, Radian Raptor charging handle so should not be an issue with the parts. Everything is torqued to spec.
lower is San Tan billet ambi, Stag LPC + POF trigger. Standard carbine spring and buffer. Tailhook mod 2.
Each time using a totally different Bolt and Carrier group.
I got hung up on using just the OKAY 20 rounders so will have to try to use the anti-tilt CProducts 30 rounders next range session.
This is a new build and now that I think more clearly about it, I am a bit more certain it's the 20rounders that have been giving me issues that I was ascribing to the BCG.
The casing is ejected, the next round is jammed tip up and with the bolt denting it about midway.
If the bolt is trying to strip two rounds from the magazine at the same time, it is because the magazine is presenting two rounds to the bolt. In this case it would be the magazine's fault
However, not sure if you are saying the rifle is trying to feed two live rounds at the same time. Is this what you are saying?
If it is just one live round failing to feed, getting that dent in the middle of the case, this usually is from the bolt missing the case and the bolt carrier itself trying to strip the case from the mag. This can be from short stroking, or the action outrunning the magazine.
Does it lock back after one round is fired from the mag?
Why a standard carbine buffer?
If it does lock back after the last round I'd put an H2 buffer in it and see if it changes anything.
In the pics above the bolt edge is caught on the back of the round and the round has its tip jammed against the feed ramp
Twenty round okay mags don't need an aftermarket anti-tilt follower. "The bolt will jam into the cartridge midsection denting it pretty badly." If the round presents at a high angle during this misfeed, in my experience this is caused by the round being stripped by the carrier and not the bolt. In my case it was caused by a loose gas key and once torqued to the proper torque (55in/lbs) it was GTG. The round partially stripped straight into the feed ramp might indicate a feed lip issue, I'd compare how the rounds present to a known good mag.
One time I bought 4 mags from and individual off GB that he originally bought as "kits", and assembled the mag springs in upside down. This caused an intermittent issue like you describe and that is an easy check.
52406
Good left, bad right...
52406
Good left, bad right...
Thanks - AFAIK the OKay Industries 20 rounders can't have the spring inserted upside down as one end has a special turned in section of spring that attaches to the follower
That didn't stop someone doing it in my case.
The upper is a 2A billet, 2A rail, Spikes 11.5, 2a Ti gas block, Radian Raptor charging handle so should not be an issue with the parts. Everything is torqued to spec.
lower is San Tan billet ambi, Stag LPC + POF trigger. Standard carbine spring and buffer. Tailhook mod 2.
Each time using a totally different Bolt and Carrier group.
I got hung up on using just the OKAY 20 rounders so will have to try to use the anti-tilt CProducts 30 rounders next range session.
This is a new build and now that I think more clearly about it, I am a bit more certain it's the 20rounders that have been giving me issues that I was ascribing to the BCG.
The casing is ejected, the next round is jammed tip up and with the bolt denting it about midway.
Does it happen when hand cycling? Slow and fast, or one or the other?
Moving it slowly, the bolt should catch the back of the rim, as shown inyour last pic. At this point, the bolt will push the round into the chamber. Can you post pic of feed ramps?
Try new mag,
Then try h2 buffer with the same 20rd mags, if problem doesnt show when hand cycling.
The pics are from hand cycling
Quickly Pulling charging handle all the way back and crisp release
Is there a lip on the feed ramps? It looks like the round is getting stuck there.
Does the barrel have m4 feed ramps?
Barrel is SPIKES BBL 5.56 11.5" FN CHF M4 EXT (SPKSB51106-LW)
It will be difficult to help troubleshoot the problem until a lock back check has been performed.
In the meantime, see how the rifle feeds when letting the BCG go using the bolt release. My initial guess is your recoil spring needs to be replaced. Judging from your description of the problem, it's possible your AR also has a weak extractor spring.
Thanks
This issue occurs with multiple different brand new bcgs
So I don’t think it’s related to the extractor spring
It also occurred with a brand new carbine buffer springs and a new sprinco red
It will lock back on last round on magazines
IIRC, your pictures indicate this occurring with the round feeding from the right side of the mag. Is this the same case in all the malfunctions?
Assuming the rifle has been supported with the same firmness throughout your experiences, locking back to the rear seems to indicate you are getting enough gas to ensure the bolt head is picking up the round.
If the bolt head, and not the bolt carrier is picking up the round, the easiest way for you to get the dented brass you describe, is for the round to be kicked upward, into the top of the chamber during feeding - often this is a feed ramp issue.
Since you have M4 feed ramps I'd check to ensure that the M4 cuts in the upper blend nicely with the M4 extension.
I would also go with an H or H2 buffer.
I had some time to check the M4 cuts in the upper
I found the transition from the cuts to the barrel extension is NOT smooth. The receiver ramp is approx .5 mm lower than the barrel ramps. So the bullet tip is forced to overcome a .5mm step
I am thinking this is causing the failures to feed and rounds getting smashed in the middle ?
I never thought to check that given the high end billet construction of the upper
I compared the m4 cuts/barrel extension transition of this upper to my Larue and a PWS and those others have very smooth and well fit transitions.
Do us a favor and let us know how it works out when you get the feed ramps matched up/
Thanks!
Dr. Bullseye
06-20-18, 23:34
It will be difficult to help troubleshoot the problem until a lock back check has been performed.
In the meantime, see how the rifle feeds when letting the BCG go using the bolt release. My initial guess is your recoil spring needs to be replaced. Judging from your description of the problem, it's possible your AR also has a weak extractor spring.
When you fire one round, just one round in the magazine, does the bolt lock back? Make just one change at a time to isolate the problem.
Do us a favor and let us know how it works out when you get the feed ramps matched up/
Thanks!
I swapped the upper receiver out for a BootLeg Enhanced LW and the M4 ramps match up without any lip. Very smooth transition.
I function checked at the range and once I got the gas tuned, Viola - no more misfeeds using those same 20 round mags
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