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Posted: 5/30/2016 5:10:24 PM EDT
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Hi all, I just finished a 300 blackout build and it has a ftf issue.
First the gun, Anderson lower, cmmg lpk, and standard carbine buffer/spring stock. Mags are pmag 30 rounders. Upper is Anderson stripped upper with kit, barrel ballistic advantage pistol length gas system, and bcg is from Daniel defense. Ammo is Remington and Barnes 300 120 grain. I could fire one or two rounds and the bolt would miss or partially pick up the next round. Tried switching to a rock river lower I have and problem traveled but it got better with the issue happening about every forth round. I have ordered a nemo 300 blk spring to try but what else? On the bright side, the gun shot one ragged hole at 100 yards with both ammo. Now to fix the feed issue and it is ready for hogs. |
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Quoted:
My first thought is a gas problem. Will the bcg lock back on empty mag? Yes, it locks back on empty mag. The bolt travel just seems to be inconsistent. It is better with the blazer ammo but the gun locks open with both on an empty magazine. Shell casings land at the four o'clock position with both brands of ammo. |
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Quoted:
I had a similar issue on a 300blk and as stated a adjustable gas block solved the issue. I will have to wait until pay day to order the gas block but I could afford to order a lighter spring and a heavier buffer to try. At least spare parts for the range box. On a side note, while I was switching lowers, an older gentleman was watching. He asked what I was doing and I explained the problem I was troubleshooting. When I had my reworked 223 mounted and tested, I asked if he had ever shot an ar. He said he did not like assault rifles. Well I offered him a chance to fire a couple of mags and he tried it. He was smiles with the ragged hole in the target at 75 yards. When I left he was at the gun counter asking to see their ar's. Another one infected with brd. |
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And just to be sure try several magazines. A weak mag spring can be the culprit as well, but being overgassed is likely the problem.
You can slow the system down with a heavier buffer as well. The adjustable gas block is nice to have, but the buffer is far easier to change out. |
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