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Posted: 3/8/2010 5:45:42 AM EDT
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A while back I built my first ar. It consists of a Spike's upper and lower, Essential Arms LPK (w/Bill Springfield 3.5# trigger job), Bushmaster Patrolman's 16" carbine barrel, YHM Lightweight carbine length forearm, PK Firearms BCG, and a Magpul CTR mil-spec stock kit.
The gun is very accurate (yesterday I shot a few 5 shot, 1/2" groups), but it is basically a single shot. When I fire, it will not eject the shell. The case shoulder stops at the front of the ejection port and that's it. I tried to clean and scrub the chamber and bolt. Then I lubed the hell out of it with CLP. Still no change. Then I thought maybe it was the buffer or spring, so I swapped lowers. The lower I used was an Essential Arms lower with a Essential Arms LPK (w/Bill Springfield 3.5# trigger job), and the Magpul MOE mil-spec buttstock kit. The same thing happened. My buddy and I were scratching our heads, so we decided to swap the bcg. My DSA upper has an LMT bcg. It feeds flawlessly, so we thought, what the heck. Problem solved. It started ejecting each and every time. The only problem we had was it would sometimes not pick up another shell. So that is my other issue. What is the issue with the PK bcg that it won't operate correctly in my build, when the LMT will? What can I do? I don't want a single shot AR. |
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there is a little "O" ring you can buy and put over the extractor spring to give it a little more power. http://www.brownells.com/.aspx/pid=24635/Product/AR_15_M16_EXTRACTOR_UPGRADE_KIT
try that and also upgrade your mags to Magpul gen 2 or 3 followers or use PMAGS by magpul |
| I was using handloads. These are 55 gr Vmax over a good charge of W748. I also tried a few different handloads with bullet ranging from 64gr down to 50, and different powders. Also, I use both pmags (latest generation) and Gi's. It didn't really matter what combo I had in. |
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With all you've done so far a lot is ruled out.. From the symptoms it could be under gassed. That is, a leak somewhere in the gas system or, if you have a gas block, the block not lined up adequately with the gas port. That is where I would look - the gas system.
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