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So I was out shooting when my AR started acting up. It would fire a round but not eject the spent case, it appeared to be short stroking all of a sudden. I pulled the bolt and installed new gas rings and that didn't solve the problem. Threw a different BCG in the gun and all worked fine. Tried a different bolt in the suspect carrier and all worked fine. Tried the suspect bolt in a known working carrier and back to short stroking.
What else could be the problem with the bolt?
Did the gas key come loose?
No it didn't. The carrier works fine with another bolt. The problem is the bolt Itself.
Extractor pin sticking out on one side and dragging into the carrier?
Post up some pics of the bolt, maybe? Might stimulate some thoughts.
If the rings were new, then all I can think off offhand (other than dragging pin as mentioned above), would be oversized FP hole letting too much gas escape. If so, there'd be telltale gas sign around the firing pin hole and on the primers of fired cases.
Without pics, this might be a remedial question but do you have a inner buffer & donut for the spring on your extractor? Ive noted if either start to wear unevenly or independently fail, it could explain the issue as you've addressed everything else I would think of. If you don't have one or both, well maybe that should be a consideration.
You'll let us know eh?
Is the ejector moving freely? If the ejector is jammed with shit it wont throw the casing making it seem like it's not getting enough gas. I would also remove the gas key and check out whats going on there. Just restake the screws when you reinstall the gas key.
I recently had the ejector freeze up from brass shavings and at first thought it wasent getting enough gas to cycle. Deffently give it a look before taking the gas key off.
Here are a few pics. I will look over ejector
http://i.imgur.com/sNWoVyf.jpg
http://i.imgur.com/KSV89fK.jpg
http://i.imgur.com/n1suyoL.jpg
Ejector, extractor...one of these things is not like the other....
I have read about a loose primer blocking the gas key port. Might have some sort of crap stuck inside. Have you run the standard pipe cleaner down the gas key?
If you have a air compressor with a blow nozzle, shoot some air inside the bolt and see what comes out. A assembled BCA will operate under compressed air at about 90 PSI.
Did you ever get a chance to figure out what was going on???
What he said^
Did you try cleaning and lubing the bolt/carrier?
Hehehe
primer down the gas tube?
I had a similar problem last year.. I put in a new ejector spring and was back in business.
Still haven't gotten out to try things again. The problem is definitely in the bolt so going to try a new extractor.
For clarity sake, it's a bolt issue.
You changed gas rings, so unlikely. Ejector or extractor isse.
Extractor - extractor worn, worn spring, or (are you using o-ring or did it blow out?)
Ejector - sticking or spring.
^ Yep. What he said.
I'm leaning on ejector over extractor by what you described. Change the ejector at home and bring a new extractor with you to the range so you can make sure which one was the bad one.
...and then you have people with bad luck like me. My F150 was throwing an EGR error which was either the EGR valve OR the valve position sensor. The sensor was cheaper, so I bought that and replaced it. Same error. So I bought the valve, replaced it and put the old position sensor back in (I'm a diagnostic engineer, FWIW). Same error. Put the new sensor back in (now new sensor AND valve) and everything's been hunky-dory ever since - they both went bad at the same time.Quote:
Originally Posted by beast556
O2
Well?
I vote ejector hang-up. Bad/tired/weak ejector spring or sticky ejector pin, as stated by others.