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Posted: 11/29/2008 12:50:22 PM EDT
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I went to the range today with my 20" Bushmaster. After firing about thirty round, I pulled the trigger and
nothing happened, no click, as if the hammer were not cocked. I cycled the action, which ejected an unfired cartridge, and fired another shot, and then the same thing happened. It looks like it is ejecting the fired case, chambering the new case, but somehow the hammer ends up uncocked. I cannot toggle the safety when it is in this mode, it is exactly as if the hammer fell, but there is no mark at all on the primer, and no click. Anyone know what might be causing this? |
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Your rifle is short stroking. The bolt carrier is not going back far enough to cock the hammer.
There are some solutions: Bad gas rings Loose carrier key Filthy and clogged gas tube/carrier key If you are using factory ammo and it is not under powered, then one of the above solutions should fix it. If it doesn't, PM me and I will help you finish trouble shooting. I just finished a re-cert at the Colt armorer's course and I have a spiffy new trouble shooting matrix :) |
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I had an upper that was short stroking due to a misaligned barrel nut/gas tube. The bolt cocked the hammer every time it short stroked, it just wasn't going back far enough to grab the next round. Since the OPs rifle is chambering the round, just not cocking the hammer, that doesn't sound like a short stroking problem.
If it's going back far enough to grab the round, the hammer IS getting pushed down, it sounds like it isn't getting locked into the cocked position or if it is, it's getting decocked as it goes back forward. Something out of spec in the trigger group? Sounds like it could also (potentially) go FA on you...If it's new I would definitely send it back for them to take a look. |
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I diagnosed it a little further here. I managed to get the hammer to release by putting the upper on and pulling the bolt back a few times. I then took the upper off and looked. The hammer is back, and it fires when I pull the trigger. If I push the hammer back down, it engages the sear and it's ok. However, if I push the hammer down a little harder, something else seems to catch, and the trigger doesn't release it. Putting it back on the upper and pulling the bolt back eventually releases it enough so it can fire. So something else besides the sear is catching and holding the hammer, it seems.
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Quoted:
Yep, there was a primer down there in the bottom below the trigger assembly. Thanks for the tip! excellent..always feels nice to fix or even know on any problem you're having. What kind of ammo were you shooting? It sounds like it happened in the first 30 rounds |
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Quoted:
This was that nickel plated cheap russian stuff from a spam can, I got it online someplace... Glad you found it. I wouldn’t necessarily condemn the ammo unless you see more blown primes with it. The first time I saw it happen was with xm193 in a colt To the best of my recollection no more blown primers in that case of ammo….. |
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