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Posted: 3/5/2016 6:35:25 PM EDT
| I installed a SLR Sentry 7 on my G2 Recon because it was not feeding the next round. I thought it was short stroking but after researching I found out that it was an over gassed issue. So I just went outside to tune the gas block and I ended up on one click from full open. Is that normal? I did install a new Spikes Tactical melonite gas tube as well. Is it possible that the factory gas tube or gas block was out of spec? Or is it possible to have just a very small amount of over gas? FWIW it runs like a top now. |
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There is a possibility that the gas block is not aligned properly now.
I installed an Odin adj block and the set screws would not line up with the dimples on the barrel. The set screw that is correct is the one closest to the trigger and the one farthest from the trigger is about 1/8" long. Check your gas port alignment and make sure it is correct. I flat filed a small flat on the barrel so the long set screw had somewhere to set. Good luck. ETA: I have a GII Hunter |
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I'm starting to think that it was under gassed after all. I looked at the old gas block and gas tube. The gas tube was rotated slightly so it was not lined up with the gas blocks port. It also looks like the hole for the roll pin was not drill straight. So that when the roll pin was installed it caused the gas tube hole to be out of alignment.
This makes sense because after installing the new gas block and gas tube It was fine. |
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Quoted:
I'm starting to think that it was under gassed after all. I looked at the old gas block and gas tube. The gas tube was rotated slightly so it was not lined up with the gas blocks port. It also looks like the hole for the roll pin was not drill straight. So that when the roll pin was installed it caused the gas tube hole to be out of alignment. This makes sense because after installing the new gas block and gas tube It was fine. Over gas and under gas failures behave just alike. Also I load one round in the mag and keep opening the gas block until the bolt will lock open on an empty mag. Then I usually go one more click open. |
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Quoted:
Over gas and under gas failures behave just alike. Also I load one round in the mag and keep opening the gas block until the bolt will lock open on an empty mag. Then I usually go one more click open. Quoted:
Quoted:
I'm starting to think that it was under gassed after all. I looked at the old gas block and gas tube. The gas tube was rotated slightly so it was not lined up with the gas blocks port. It also looks like the hole for the roll pin was not drill straight. So that when the roll pin was installed it caused the gas tube hole to be out of alignment. This makes sense because after installing the new gas block and gas tube It was fine. Over gas and under gas failures behave just alike. Also I load one round in the mag and keep opening the gas block until the bolt will lock open on an empty mag. Then I usually go one more click open. That's what I did and ended up one click from full open. It is mid length gas. I'm happy and not going to worry about it to much since its running fine. It was just odd because I was expecting to cut the gas down a lot. |
| Six, is this a new rifle? About how many rounds through it when it failed to fully cycle? While I think you properly corrected what appears to be a gas tube alignment issue, I don't find it unusual for some AR's, big and small caliber, to have minor cycling stiffness until a few rounds are fired...manufacturing tolerances, etc. On your mid-length gas system, did I miss how long the barrel is? I have an Armalite AR10 .308 16" carbine with mid-length gas that I built. The fixed, factory gas block had the brass consistently hitting at 1 o'clock with a sharp but not annoying recoil...especially compared to my 20" Armalite .308...logical. My 16" carbine had the Armalite factory extension tube and buffer system that was set up for a 20", rifle gas, .243 barrel. I installed a JP adjustable gas block, and now the recoil is about as mild as my factory setup 20" version with brass going at 4 o'clock. In my AR15 builds, I have noticed mid-length gas doesn't usually require a heavy buffer or adjustable gas. However, the .308 AR seems to react a little differently. And, there is the issue if understand correctly that the GII DPMS uses noticeably lighter components, especially in the BCG. This probably throws another different element into the gas/recoil/cycling mix compared to what many of us experience with "more common" .308 AR builds. All that said, if you're getting reliable cycling with the gas tube alignment addressed with the adjustable gas block, I'd leave it as is...unless you end up running some really weak ammo. As already suggested, you'll appreciate the adjustable block if you start shooting suppressed or shoot widely varying ammo. |
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This is a brand new rifle. When I first took it out last Thursday it would only fire one round at a time and not pick up the next round. So I thought it was over gassed, that's why I bought the SLR. I think if I had seen the gas tube issue and drilled out the bit of gas tube overlapping the gas block it would have fixed the issue. As it breaks in I'll fine tune the adjustable gas block. I'm glad i listened to everyone on hear and didn't just buy a heavy buffer. |
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