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I know this is a common issue. And maybe the answer is I should just keep tweaking it. I'm hoping so. I have built other ar's with no issues. I have an arperformance 6.8 20 in barrel rifle length gas I believe. I built for my dad several years ago. It seems like from day one we have had feeding issues. I switched to a jp adjutable gas block. Tried to tune the gas.
Basically what was happening was and is that that the bolt would move back after the shot but not fully seat every other round or three. It is a Daniel defence bolt carrier group. After messing with the gas and not getting any where I got odin works adjustble buffer weights and tried those today. I upped the weight and that seemed to fix the problem of having enough inertia to close the bolt after firing but then that meant that it would not go back far enough and cycle at all and pick up the next round again every other round or three.

It is wierd because it will not happen every time. Only if you shoot a couple times in a row. And not even in very rapid succession.
As I am writing this I am wondering if some how we bent the upper when building the rifle and it's just two tight. It just always seems tight to me. But I can hand cycle it just fine. It does have a couple hundred rounds through it now.

Any other ideas?
 

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If it is rifle length gas you will be limited with powder choices. Open the gas port wide open as you are not getting enough gas to cycle the carrier properly. You can search the forum for loads that work in rifle gas.
 

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Do you have the gas block seated all way again the shoulder? I was having gas issues(not farts) and found online someone used a credit card to space the block away from shoulder. Ive done that to every rifle since and not had anymore issues. My ARP even has a little edge where the CC will fit. May not be issue but something to check!
 

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If it only does it intermittently it's probably minor. Pull your bcg and check for unusual wear marks on all surfaces in the upper and on the bcg. If you see nothing unusual and it cycles fine by hand I would look at a gas issue. Double check your gas block alignment. You didn't say what ammo u r using. If reloads try some new Hornady. If all this fails I would think about going up a size on the barrel's gas port. Good luck with it.
 

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Discussion Starter #5
If it is rifle length gas you will be limited with powder choices. Open the gas port wide open as you are not getting enough gas to cycle the carrier properly. You can search the forum for loads that work in rifle gas.
I was afraid this was the answer. I kind of talked my dad into this cartridge. We didn't realize the shortcomings of the rifle length gas system when we bought it and he only will ever shoot fs tory ammo. Is there any modification that I can do to the system to reliably shoot factory? Or would I be better off trying sell this barrel and getting a mid length gas system for him?
 

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I found an old post where Constructor states 093 gas port should work if good build practices are used, but he ports them now at 098 in case of any leaks. What factory ammo is dad using? Remington and some of the Nosler/SSA are underpowered.
 

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I found an old post where Constructor states 093 gas port should work if good build practices are used, but he ports them now at 098 in case of any leaks. What factory ammo is dad using? Remington and some of the Nosler/SSA are underpowered.
Ok so that may be helpful. I stocked up on pretty much exclusively ssa. Yesterday we shot 110 barnes tsx, 100 nosler bonded. I just grabbed a couple boxes of what I had. But as I said I had stocked up several years ago on ssa and that is what we have been shooting for awhile.
 

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EVERY barrel we sell is dimpled, put the rear set screw IN the dimple and that will align the gas ports.
 
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Discussion Starter #10
EVERY barrel we sell is dimpled, put the rear set screw IN the dimple and that will align the gas ports.
I have three other of your barrels with midlength gas systems that run perfectly. I love them. I just didn't realize the issues we might face when we bought this rifle length gas system. It was mentioned that you have increased the diameter of your ports. If I measure and I have the older smaller port size do you recommend that I go ahead and drill it out to a bigger size? I don't remember exactly when we bought the barrel I would say 5 plus years ago. Not sure when you started making the gas port bigger.

Or do you think this older ssa ammo is the issue? Do you have a suggestion of factory ammo that my dad can buy and use? He doesn't need anything special. He is not a hunter but wants a round that can kill a deer if needed. And obviously looking for something that he can stock up on.
 

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Yes drill it out to .096 or .098. Older SSA should be fine, when Nosler purchased SSA they down loaded everything.
 

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I'm a clamp or pin FSB kinda guy. :)
That little hole on the bottom of every gas block is how they drill the port in the top, align the little hole in the bottom of the GB with the dimple.
 
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Go to General>Docu Database>Tips, Tricks, etc. Then go to Post #2 (it’s a cut and paste from Constructor). Details gas block issues and how to correctly install. I have followed those instructions exactly on my adjustable gas block installs and have had no problems, including a rifle length barrel.
 

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I had a similar issue with a mid length gas system. When I took everything apart there was a shiny area on the gas tube where it enters the carrier. The gas tube was slightly bent causing extra friction on the carrier. I replaced the gas tube and all was well.
 
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