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JP SCR-11 leaking gas between Upper and barrel nut


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As some of you might know I just got back from Afghanistan. I have been cooped up in a hotel room for 2 weeks and bored out of my mind. I have been doing a lot of dry fire practice and handling my guns. Thanks when I noticed something odd about my JP SCR-11. I noticed that gas appeared to be leaking between the upper receiver and the barrel nut. I Also noticed that the gas tube has a little play in it. I can put my finger on the gas tube inside the upper receiver and wiggle it to the point that it makes a rattling noise. I bought this rifle about 2 years ago and only have about 500 rounds through it.

I was in the process of developing a load for it but a deployment got in the way. While trying to develop a load I noticed that my groups were a little loose. About 2.5-3 inch groups at 100 yards. Could the leaking gas and loose gas tube be a cause for this? Is it a major issue? I have built several uppers and none of them have loose gas tubes. Should I attempt to contact JP?

post-34074-0-61458900-1364697531_thumb.j

post-34074-0-67548600-1364697748_thumb.j

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As some of you might know I just got back from Afghanistan. I have been cooped up in a hotel room for 2 weeks and bored out of my mind. I have been doing a lot of dry fire practice and handling my guns. Thanks when I noticed something odd about my JP SCR-11. I noticed that gas appeared to be leaking between the upper receiver and the barrel nut. I Also noticed that the gas tube has a little play in it. I can put my finger on the gas tube inside the upper receiver and wiggle it to the point that it makes a rattling noise. I bought this rifle about 2 years ago and only have about 500 rounds through it.

I was in the process of developing a load for it but a deployment got in the way. While trying to develop a load I noticed that my groups were a little loose. About 2.5-3 inch groups at 100 yards. Could the leaking gas and loose gas tube be a cause for this? Is it a major issue? I have built several uppers and none of them have loose gas tubes. Should I attempt to contact JP?

Chris I would love to look at that rifle for you some time. The gas tube has some play because its only solidly connected at one point in the gas block. It is braced by the barrel nut but it is not locked in there so yes you should be able to move it a bit if you try. I would turn your gas system all the way down and fire 1 bullet at a time with an empty mag. Once it locks back go just about a half turn to a full turn past that and lock tight it in. But do that with the weakest ammo you shoot. As for groups what ammo are you using? Cheap ball is not going to be great in any rifle. My JP runs my 55 grain reloads at 1.5 to 2 moa. It averages .85 or so with match reloads. Next time I see you I could give you a handfull of bullets to try that I know are accurate.

Pat

Edited by Alaskapopo
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As some of you might know I just got back from Afghanistan. I have been cooped up in a hotel room for 2 weeks and bored out of my mind. I have been doing a lot of dry fire practice and handling my guns. Thanks when I noticed something odd about my JP SCR-11. I noticed that gas appeared to be leaking between the upper receiver and the barrel nut. I Also noticed that the gas tube has a little play in it. I can put my finger on the gas tube inside the upper receiver and wiggle it to the point that it makes a rattling noise. I bought this rifle about 2 years ago and only have about 500 rounds through it.

I was in the process of developing a load for it but a deployment got in the way. While trying to develop a load I noticed that my groups were a little loose. About 2.5-3 inch groups at 100 yards. Could the leaking gas and loose gas tube be a cause for this? Is it a major issue? I have built several uppers and none of them have loose gas tubes. Should I attempt to contact JP?

Chris I would love to look at that rifle for you some time. The gas tube has some play because its only solidly connected at one point in the gas block. It is braced by the barrel nut but it is not locked in there so yes you should be able to move it a bit if you try. I would turn your gas system all the way down and fire 1 bullet at a time with an empty mag. Once it locks back go just about a half turn to a full turn past that and lock tight it in. But do that with the weakest ammo you shoot. As for groups what ammo are you using? Cheap ball is not going to be great in any rifle. My JP runs my 55 grain reloads at 1.5 to 2 moa. It averages .85 or so with match reloads. Next time I see you I could give you a handfull of bullets to try that I know are accurate.

Pat

gonna be at birchwood tomorrow?
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I know I have a pound a varget in storage but I'm not sure what it is. I'll be headed to the lower 48 for 20 days on the 3rd. I was hoping to figure out if I should send the upper to JP before then. It sounds like a little play in the gas tube is ok and I need to back off the gas block a little. So hopefully it's nothing big and I will be good to go once I get back from leave. Just a few adjustments needed.

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+1, 100% normal...

The passage in the upper receiver for the gas tube is "clover leafed" to allow gas to escape (forward). On an AR-15 with a standard hand guard, the slip ring (delta ring), weld spring and lock ring will have significant fouling on high round count rifles and carbines.

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