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Posted: 4/25/2011 11:55:27 AM EDT
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First time poster with a trigger problem.
I am a service rifle competitor with a Bushmaster AR and a Rock River Trigger. During my rapid fire stages, I noticed a loud click in my rifle when I squeeze the trigger. The problem occurs after I have fired my first shot and the bolt cycles the next round. As I release the trigger, there is a loud click when the trigger resets. I was unaware that this was not normal until several competitors asked me, "do you know your gun makes a loud clicking noise?" The gun continues to function properly, with the exception of the bolt failing to lock back after the last shot. But I believe that is a separate issue. Any help would be greatly appreciated. Thanks. |
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The click is the release of the hammer off the disco and resetting to the trigger sear, which is normal.
As for the bolt not locking back, could be the ammo (heaver grain ammo using slower burning powder cause excess gas pressure at the B/C to cause the bolt to try to unlock too soon), the sled/mag not activating the bolt catch correctly, or even a leak from the carrier to the key, with not enough pressure for a full stroke. |
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Thanks for the feedback! Is this specific to the Rock River triggers? I don't hear the same click on factory Bushmaster triggers.
As for the Ammo, I am using a 75 grain bullet with 23.6 grs of RL15 and a 77 grain SMK with 24.0 gr's of RL15. I think those are close to Max loads. I also have friends using the same loads with no problems. I think part of my problem was a filthy bolt. After I cleaned it thoroughly, the frequency decreased however it did fail to lock back a few times. |
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Give the trigger some time to settle in,and it will produce less noise on reset.
As for the powder and peak pressure at the barrel gas port, take a look at linked topic below to give you an idea. The chart shows H-335 powder, and with your slower burning powder, you peaks on the chart would be farther to the right on the chart, meaning more pressure that the gas port/BC is seeing, so not only more pressure to the system, but the system unlocking faster while the spent case is under a great deal more residual bore pressure for the bolt to have to pull the spent case out of the chamber. http://www.ar15.com/forums/topic.html?b=3&f=66&t=266108 And if you where wondering about the Tubb's carrier weight system, it was designed for just these conditions, which it adds mass to the carrier to slow it back down at unlock to allow the bore pressure to blead off before the spent case is chamber pulled. |
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