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Posted: 8/28/2013 9:37:23 AM EDT
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My initial problem was in the post below:
Round 1 I have since changed to a ICE arms 7.5" barrel, Phase5 pigtail gas tube and a Spikes H2 buffer. (also using good ammo this time too) Off to the range today, 1 round in a Pmag for test purposes. It goes boom, doesn't extract and doesn't lock the bolt open. Tried "grenading" as I think I have heard it referred to by slamming the end of the tube on the ground. No luck. Shell easily tapped out with a rod though. I'm starting to think I may have an issue with my bolt extractor and I know I have some sort of a gassing issue. My superbolt will be here later this week so I'll be able to test that issue, but whats my next move for getting the gas right? |
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Quoted:
have you taken the bolt out and removed the pin for the extractor to see if a chip of brass is stuck in it ? got a pic of your gas block from the side ? is the gas block all the way against the shoulder ? Block is fully seated, I reassembled the whole thing prior to today. I can check the extractor, but I doubt it as the bolt has only seen about 10 rounds total |
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the gas block should not be fully seated against the shoulder they are not designed for that they are meant to have the hand guard ring between the shoulder and gas block .... your gas hole and block are not lined up .... and it only takes one round with a weak rim to get a piece stuck in the extractor hook or maybe your missing a the rubber insert in the spring or you need to add a o-ring to give it more power
ETA and yes i know you are using a free float rail and dont have the ring on it |
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Quoted:
the gas block should not be fully seated against the shoulder they are not designed for that they are meant to have the hand guard ring between the shoulder and gas block .... your gas hole and block are not lined up .... and it only takes one round with a weak rim to get a piece stuck in the extractor hook or maybe your missing a the rubber insert in the spring or you need to add a o-ring to give it more power The barrel has two indents for the set screws so I know it's not misaligned. I may get another gas block to try as this one was pretty cheap. |
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Looking at the pic above, is the gas tube entering the receiver centered? Looks off… in the photo anyway… and does it go in far enough… the end of the tube that enters the gas key should have a lip and form a seal…
Make sure the 3 gas rings on the bolt are doing their job… does the bolt slide back and forth too easily? Make sure the seams in the rings don't line up or gas will pass there. Is the barrel indents set up for the screw locations of a different block? I'd put some witness marks on the barrel coming from the gas port, and put some witness marks in the block coming from its hole, and then line them up. Using calipers would make it exact, but you can use a ruler. Do that, get that out of the way, even if it is good now, it's nice to 100% certain. I wish we had some kind of gas pressure delivery device dingus that we can deliver into a barrel to check its function at home. Range fees, ammo cost, time, etc is expensive - going back and forth testing. I just finished my first build and I'll be going to the range in the next couple of days with my fingers crossed. I'll have a standard action spring plus a blue Sprinco, and a standard buffer and a H2 buffer - and 4 different brands of ammo, three .223 and one 5.56. 
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| I had a similar issue with my 7.5 barrel pistol. I'm running a BCM BCG. The BCG came with a grommet/o-ring. After I had 3 or 4 failure to extract malfunctions, I took the extractor off of my bolt, placed the o-ring over the spring and reassembled. Several hundred rounds now without a failure to extract. Good luck. |
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