Big Problem with my AR-15

All good suggestions folks but the OP stated in the first post that his rifle worked just fine for 300 rounds. The bolt carrier is just a hunk of steel that houses the bolt. Gas goes into the gas key and is ported into the cavity that houses the bolt causing it to to rotate out of of battery and causes the BCG to move back. Try blowing into the gas key and see if there is an obstruction that prevents proper operation. The pictures of your bolt carrier all look normal. If there's no blockage in the gas key, then I'm out of suggestions. It's the only thing that's left as far as I can figure.
 
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check tightness and position of gas block... check extractor and ejector on bolt head...blow some air through gas tube to check for obstructions....I think every other possible thing is mentioned.. Worn or seized/cracked/chipped extractor can be an issue.
 
bobbynewmark said:
check tightness and position of gas block... check extractor and ejector on bolt head...blow some air through gas tube to check for obstructions....I think every other possible thing is mentioned.. Worn or seized/cracked/chipped extractor can be an issue.
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Read the previous posts. The gun works fine with another bolt carrier.
 
RifleDude said:
All good suggestions folks but the OP stated in the first post that his rifle worked just fine for 300 rounds. The bolt carrier is just a hunk of steel that houses the bolt. Gas goes into the gas key and is ported into the cavity that houses the bolt causing it to to rotate out of of battery and causes the BCG to move back. Try blowing into the gas key and see if there is an obstruction that prevents proper operation. The pictures of your bolt carrier all look normal. If there's no blockage in the gas key, then I'm out of suggestions. It's the only thing that's left as far as I can figure.
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Thanks for straightening everyone out :) I plan on sending it in for warranty there is nothing obvious here and no blockages.

thx everyone for your suggestions.
 
shoota said:
Thanks for straightening everyone out :) I plan on sending it in for warranty there is nothing obvious here and no blockages.

thx everyone for your suggestions.
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You got a little zip tie or something to force into the bolt carrier key to see if it's blocked?

Also, something I haven't seen suggested, is see if your charging handle got bent. A bent handle may still insert into the receiver, but the tight fit of the gas key could cause enough friction to short cycle it, and if it's a looser fitting key the other carrier may work when you tested the second bolt carrier. That could definitely happen after the fact if you rack the run from the side.
 
rambones said:
so you put another BCG in and it works fine??

Therefore its your original BCG not working?

Also it is not picking up another round but ejects?

sounds like short stroking.

check your gas rings
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Me thinks herein lies the problem, except 300 rds is very premature for new rings.

shoota said:
Will try to find some gas rings locally and try that before returning. Will update.
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You already have a spare set on your other bolt. You have swapped the BGCs, and the problem moved. Now swap the bolts within the BCGs and see if the problem moves. Follow the defect. IF the bolt is the problem, try swapping the gas rings between the bolts.

That said, a problem that moves with a part could certainly be indicative of the problem part, or it could be coincidence. If you can get a third AR and BCG then you can be significantly more confident if the problem migrates with the BCG to a third rifle.

I have a bushmaster XM15, and at around the 18,000 mark, long after accuracy became poor, I started getting the exact same stoppages you described. I replaced the gas rings and gas tube and she ran like new, except sadly, accuracy remains a problem. :(

Why buy a new barrel when you can gift the whole thing to the wife and buy yourself a new rifle...

Sarge_DL said:
Long shot: Any chance you have a litle scale to see what both of thise BCGs weight? If the the one that is not working is heavier, then you’d need to change either buffer weight, spring weight, or the amount of gas going into the BCG.
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The gun worked fine. Bolt weight won't be an issue, as bolts don't get heavier, although the spring could have gone soft. Again, 300 rds is very premature for this, but it has to be something.
 
Can you try to get a better picture of the inside of the carrier? It should be polished smooth in there where the gas rings ride, if it's not that would explain worn gas rings after 300 rounds.
The earlier picture looked like it was not smooth but the angle made it hard to see very well.
 
cr5 said:
Can you try to get a better picture of the inside of the carrier? It should be polished smooth in there where the gas rings ride, if it's not that would explain worn gas rings after 300 rounds.
The earlier picture looked like it was not smooth but the angle made it hard to see very well.
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I posted above it's smooth, and it's not the gas rings, ruled that out long ago with a bolt swap, troubleshooting is done boys she is going in for warranty. I will update with what they do.
 
Got the rifle back. Pretty quick turn around time and they didn't say what they did to it but by the looks there is a new BCG in there. Returned dry as a bone so after some lube took it out for a spin and it's back to working order.
 
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