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Posted: 7/24/2008 6:28:03 AM EDT
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I posted this on the other forum , but I have a 11inch COLT A1 upper with the tear drop- oval forward assist, the upper is on a new RRA Pistol Lower- The upper- using NEW MAgs, New AMMO- will shoot once- then fail to extract the spent shell , the bolt will strip a new round out of the mag jamming it into the primer of the stuck case in the chamber. I took everything apart , cleaned & inspected it. The extractor is fine - but I installed a D Ring to be safe , & the same thing happened. I also installed a second Bolt Carrier group & it still did the same thing. ANY IDEAs......... Do pigtail gas tubes help? make it hot please!! - http://www.ar15.com/forums/topic.html?b=3&f=118&t=387866 |
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www.ar15.com/forums/topic.html?b=3&f=118&t=387866 HOT What ammunition exactly? Is it failing to extract or eject (I'm assuming extract, since you replaced the D ring) What marks are left on the brass it fails to extract? Do you have a means of checking chamber dimensions (seems like that might be the issue - somebody dumped a tight chambered barrel onto that upper) |
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I've been reading rumors on a few other sites that other people have had some of the same problem with that same ammo. And from what I have gathered it is or was over pressure, expanding the cases making it real tight and hard to get out of the chamber. I would suggest trying a different type of ammo and see where that takes you. If another type of ammo does the same thing, you might want to have you chamber checked, head space, throat, and chamber gauged. If any of that doesn't pass have it reamed just enough to open it up, but not to much. |
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Granted that the upper receiver is Colt, whom is the barrel by. The Colt XM-177E2 or commando barrels should not have a chamber problem is still fresh (there where reamed SBR from the start). Is this a Non-Colt commercial, or cut Colt barrel just reamed standard Nato or 233 (read too tight for a SBR length barrel)? |
| This might put some light on the subject, I had the same problem when I replaced my bolt carrier group, I thought it was the ammo, I even thought it was the barrel it's self, then I started by looking at the gas tube, it was bent, so I replaced it, then I saw a vid about barrel replacement and the guy said to check to make sure that the gas tube is not hitting on anything, so I did that, lo and behold, when I put the new gas tube in before doing anything else, just by setting it on top of the barrel and closing the bolt, the gas tube was being pushed forward causing the gas tube to be bent, luckly I had a spare gas key, replaced it and it did not move, thus it told me the the gas key is to blame, and the new BCG is DPMS, I never had a problem in the past until I bought the new BCG, I even reload, and a friend of mine said the ten rounds I gave him worked perfectly, so check out the gas key, all this because I even thought it was the barrel, which I bought a new barrel, which I will have installed, so I hope this helps, even some things you don't think about can be the problem... |
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im having the same problem with a capco/martin marrietta govt contract upper (11.5 bbl, used) that i bought recently. it worked for about two mags then started failing to extract. i checked the extractor as well. . . its fine, and so is the rest of the bolt. is this a common problem? its the first AR ive ever had do this. . . sort of ruining my retro AR deal. |
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