If this is a brand new gun, take out the bolt and clean the crap out of the chamber with a brass brush and cleaner. I mean really clean it and then get it nice and lubed up. I had the same problem with Wolf and I did that. It helped a lot. I switched to Hornady .223 and it works just great. Good luck.
Calling all AR-15 Gurus! FTE/FTF issues.
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primalmu
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Thanks guys. I'll keep all this in mind. I might be able to hit the range this week sometime and give it a test with full power ammo.
WinThePennant
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I might have missed this, but what is the length of the gas system?
redneck2
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I had a SOCOM that would not cycle. Tried different loads, bullet weights, spring work, mags. Did everything but the obvious. Finally just lubed the crap out of it and it's functioned fine ever since.
michael5446
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polish the feed ramps and make sure there are no sharp edges, if the ramp/action damages the brass you will have feed problems...
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primalmu
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WinThePennant, it has a rifle length gas system.
WinThePennant
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Run the o-ring.
Fail to extract? And fail to feed maybe short cycling? I suppose the latter can relate to the former, if there is a lot of resistance to extraction there may not be sufficient power left to full cycle, it may not be gas related. That can happen with steel cases... you are using brass, right? Something can be causing the cartridges to stick in chamber after they expand from firing. Normally the cases expand to fill the chamber and then bounce back to be loose for extraction. Steel cases don't bounce back which is why they are coated with lube. If the chamber is tight, isn't smooth, or has a deformity the cases can stick.
If the bolt sometimes doesn't want to close it may be this resistance to chambering the cartridge. With magazine in place it may be aggravated by more resistance. Bear in mind that bolt carrier needs to slam shut, the charging handle lock can prevent the bolt from just sliding shut gently.
Have you inspected the spent cases? Look for deep scratches or gouges, signs of pressure expansion like a bulge, and especially check around the case rim for torn brass where the extractor ripped free of the case rim. Look for pieces of brass under the extractor, and look for evidence of extractor malfunction, chips or breaks. These can also result from over pressure so try other barns of cartridges as others suggested (maybe not all PMCs are all that precise). Check extractor function and that the spring is strong and there is a nylon insert inside spring to tighten it all up, even better a nylon ring around it. If you have another AR consider swapping the bolt carrier assemblies to eliminate extractor failure.
Check closely inside chamber for obstructions or roughness. Try to see down in throat if there may be a piece of previous case throat lodged in there. Can you slide a shell all the way into chamber and pull it out without much resistance? What can be happening is case expands and sticks in chamber just long enough that bolt rips extractor free before case bounces back in size... but I wouldn't expect this in a rifle length gas system as it would take longer for the bullet to reach the gas port thus taking a bit more time before bolt extracts case.
You may have gotten an out of spec chamber. Just thinking
If the bolt sometimes doesn't want to close it may be this resistance to chambering the cartridge. With magazine in place it may be aggravated by more resistance. Bear in mind that bolt carrier needs to slam shut, the charging handle lock can prevent the bolt from just sliding shut gently.
Have you inspected the spent cases? Look for deep scratches or gouges, signs of pressure expansion like a bulge, and especially check around the case rim for torn brass where the extractor ripped free of the case rim. Look for pieces of brass under the extractor, and look for evidence of extractor malfunction, chips or breaks. These can also result from over pressure so try other barns of cartridges as others suggested (maybe not all PMCs are all that precise). Check extractor function and that the spring is strong and there is a nylon insert inside spring to tighten it all up, even better a nylon ring around it. If you have another AR consider swapping the bolt carrier assemblies to eliminate extractor failure.
Check closely inside chamber for obstructions or roughness. Try to see down in throat if there may be a piece of previous case throat lodged in there. Can you slide a shell all the way into chamber and pull it out without much resistance? What can be happening is case expands and sticks in chamber just long enough that bolt rips extractor free before case bounces back in size... but I wouldn't expect this in a rifle length gas system as it would take longer for the bullet to reach the gas port thus taking a bit more time before bolt extracts case.
You may have gotten an out of spec chamber. Just thinking
the count
Member
You built this gun yourself, right? You know what headspace is? If thats off, you have a potentially dangerous gun.
PS Just re-read your OP. The bolt, bolt carrier, barrel, etc was bought as a unit? then dont worry about headspace.
You should simply take the gun to a good gun smith if you have one in your area. He might charge $30-50 to look it over just to make sure its not something obvious (to him, not to you) and that its basically safe.
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chrome_austex
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Check the gas port in the barrel to gas block alignment, that sounds like the most likely culprit. While the gas block is off, check and make sure its not clogged or defective.
Make sure the carrier is well lubed and try a PMAG if you haven't. (I've got a gun that runs great, but double feeds with steel mags and steel cased ammo)
If the gas port is in alignment, the carrier moves freely, and you're using full strength brass cased ammo out of a PMAG, then I'd be looking hard at the buffer setup.
Make sure the carrier is well lubed and try a PMAG if you haven't. (I've got a gun that runs great, but double feeds with steel mags and steel cased ammo)
If the gas port is in alignment, the carrier moves freely, and you're using full strength brass cased ammo out of a PMAG, then I'd be looking hard at the buffer setup.
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primalmu
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@awgrizzly: Thanks for the suggestions, I'll definitely reference your post as I troubleshoot further (which like I said earlier will depend on when I can get to the range). I've also got a Wolff HD extractor spring and some o-rings on the way. Oh, and I used primarily brass ammunition, although I did run some steel-cased through it while trying to troubleshoot. No change in function between the two.
@the count: Yes, I bought the upper complete. BTW, in my reading there seems to be a controversy over headspacing in ARs. Some seem to say that the AR design automatically headspaces itself (also asking the question of what adjustments would you take to adjust the headspace of an AR as further evidence), while others say that they in fact do need to be headpaced. I will look into this further.
@chrome_austex: I did try a PMAG and had the same issue. Admittedly, after I cleaned my AR I realized that the BCG wasn't well lubed. I'm hoping that this is the source of my problems. Rest assured, it is lubed up good now and is awaiting another trip to the range.
@the count: Yes, I bought the upper complete. BTW, in my reading there seems to be a controversy over headspacing in ARs. Some seem to say that the AR design automatically headspaces itself (also asking the question of what adjustments would you take to adjust the headspace of an AR as further evidence), while others say that they in fact do need to be headpaced. I will look into this further.
@chrome_austex: I did try a PMAG and had the same issue. Admittedly, after I cleaned my AR I realized that the BCG wasn't well lubed. I'm hoping that this is the source of my problems. Rest assured, it is lubed up good now and is awaiting another trip to the range.
Redlg155
Member
Headspacing can be checked by a set headspacing guages, a relatively easy process. The majority of folks don't worry about it when using a NEW bolt. However, swapping a used bolt can lead to problems. In addition, headspacing requires a set of specialized tools and knowledge to do it right. Definitely not a task for a "unit level" armorer.
It definitely sounds like a gas problem. I know it sounds strange, but I wouldn't rule out a gas tube installed upside down.
It definitely sounds like a gas problem. I know it sounds strange, but I wouldn't rule out a gas tube installed upside down.
Rule 9- No matter what type of malfunction a shooter is having with an AR, someone will suggest the rifle is over-gassed before the thread reaches Page 3
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primalmu
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Not yet. Right now I'm at the mercy of other people's club memberships, haha. Might be able to hit up a range on Friday though.
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primalmu
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Okay, finally got back out to the range. I put 60 rounds through my rifle without any FTEs or double feeds. Between cleaning the rifle, a liberal application of lube, a heavy duty extractor spring, and an extractor spring o-ring, the rifle operated nearly flawlessly. The only issue I had was a single failure to remain open on empty (out of about 10). Not a big deal and I figure it will sort itself out as I break the rifle in.
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primalmu
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Oh yea, it ran milspec 5.56 NATO as well as .223 Rem perfectly.
1) Lube the heck out of the BCG and go shoot some full-power 5.56 ammo. Your FTE issues are due to insufficient gas pressure. Your FTF issues have the same cause: the BCG isn't traveling back far enough to strip the next round off the magazine.
2) If what I described doesn't work, you have a problem in your gas system. Check to see if your gas keys are properly staked, that your FSB is pinned and straight.
EDIT: I see that the full-power ammo sorted out most of your issues, but you had one failure to lock back. That's still symptomatic of a leaky gas system. I suggest you look at my point 2 above.
2) If what I described doesn't work, you have a problem in your gas system. Check to see if your gas keys are properly staked, that your FSB is pinned and straight.
EDIT: I see that the full-power ammo sorted out most of your issues, but you had one failure to lock back. That's still symptomatic of a leaky gas system. I suggest you look at my point 2 above.
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