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Posted: 11/9/2009 11:21:40 AM EDT
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I finished an SBR build. 11.5" Adco barrel, Daniel Defense BCG, RRA upper and lower receivers, Gasbuster CH, milspec fire control w/ a Springfield trigger job.
The gun shoots great and had no problem digesting the first 150 rounds I put through it, mostly Centurion and Prvi M193. Cycles and ejects perfectly. No problems of any kind. I noticed, however, that when I manually operate the action to clear an unfired round, it is very, very stiff. I really have to yank the CH. It's locked tight as a drum but then releases and ejects after enough force is applied, but it is definitely stiff. It takes quite a pull. To be clear, I'm talking about ejecting chambered but unfired rounds from a cold, clean gun. It isn't a problem with one particular cartridge. It happens consistently with any ammo. Any thoughts? Is this a break in issue? Too little headspace? |
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Quoted:
I finished an SBR build. 11.5" Adco barrel, Daniel Defense BCG, RRA upper and lower receivers, Gasbuster CH, milspec fire control w/ a Springfield trigger job. The gun shoots great and had no problem digesting the first 150 rounds I put through it, mostly Centurion and Prvi M193. Cycles and ejects perfectly. No problems of any kind. I noticed, however, that when I manually operate the action to clear an unfired round, it is very, very stiff. I really have to yank the CH. It's locked tight as a drum but then releases and ejects after enough force is applied, but it is definitely stiff. It takes quite a pull. To be clear, I'm talking about ejecting chambered but unfired rounds from a cold, clean gun. It isn't a problem with one particular cartridge. It happens consistently with any ammo. Any thoughts? Is this a break in issue? Too little headspace? I wouldn't worry about it. New guns are usually a bit tight. |
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It shot great on the first outing, but it was only afterwards that I noticed unchambering a live round was difficult. Since then, I haven't shot again until I make sure this isn't a safety issue.
I'm talking about having to hold the gun muzzle down and pull HARD on the CH to get the round to eject. I probably should have used a stronger word that "stiff" in the title of my post. It's beyond new gun stiffness, at least in my limited experience. It's nearly locked up. Not saying it isn't an issue of break in –– I've played with Les Baer 45s that were so closely fitted that you could hardly rack the slide at first –– but this seems excessive. |
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Okay. More data points:
I pulled out another AR with, maybe, 3K rounds through it. If I put the BCG from the problem rifle into the other AR, it works perfectly. No problems extracting. Likewise, when I put the other AR's BCG into the problem rifle, it works fine. Extracts with no undue effort. In other words, both the upper and the BCG seem to function normally, except when paired together. When you put them together, it is very difficult to unchamber around. Tonight, I had to resort to the "bang the buttstock on the ground while pulling CH" method. It's that tight. However, the components seem fine separately. Any thoughts? PS. Used new brass dummy rounds, not live ammo, so don't jump my @#$. PPS. Chamber cleaned again and bolt lugs and barrel extension well lubed. |
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Does the ammo show any marks on the bullet? That is, are the bullets contacting the rifling?
When I installed a BCM bolt in my Stag 3, lockup was noticeably tighter compared to the stock CMT bolt and a RRA bolt I had on hand. I ran the BCM bolt through a few matches, maybe 300 rounds, and it's loosened up a bit. |
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