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Posted: 9/6/2007 10:59:27 PM EDT
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First let me say I haven't posted here often but I've been surfing the site for awhile and gleaning knowledge. Site is always helpful and I especially enjoy making the missus mad with the EE have My new (+/- 300 rd count) Bushy doubled on me today at the range. I spent the rest of this evening tearing apart the trigger group and ensuring proper fit, function and whatnot accoding to the FAQ here and found nothing amiss that I could see. I have never had a rifle do this in all my time in the military, and I was just wondering if it's a fairly common occurrance that I have just avoided or not made note of in the past, or if it is something I should be more concerned about. Thanks for your replys in advance. |
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The more I think about it the more I wish I had built an LMT or something similar. That's what the next one will be. As far as my bushy is concerned however... It's a work gun, I need it to perform. Should I be overly concerned with this problem or should I just wait till it happens again before I panic and try to send it back? Like I said I did take a look at the FCG and found nothing out of the ordinary that might have caused this. I guess my question is could it have been a fluke occurrance or will I see an increase in frequency? |
If it's your "Work Gun" you need to get it figured out NOW. A properly functioning AR, regardless of the maker should not double. Hopefully "Dano" will chime in here on recommended fixes. Tack |
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Yeah I know it needs to be fixed. I'm gonna go back to carrying the 12 gauge tonight at work until I can figure it out. Problem is nothing looks wrong with it in the fire control assembly. It functions properly now, and I went through about 150 rounds after it doubled without a problem. |
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Are you sure it doubled. or did it "bump fire". For any that may NOT know....a double is two shots fired by the rifle with ONE press of the trigger. This is usually caused by a disconnecter/hammer problem. A Bump Fire is caused be a loosely held rifle where the recoil of the rifle, along with the loose hold, actually causes the rifle to quickly fire two rounds by a "rebound"affect on your trigger finger. The reason i ask, is usually when a rifle doubles, it will do it pretty regularly (since parts don't "fix" themselves. It is possible some debris could have caused the hick-up as well, but rare. |
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www.ar15.com/content/guides/assembly/lower/ First off, pull the FCG and check for debris under the trigger. A blown primer cup or primer anvil under the trigger can cause the problem. Once the receiver has been checked, then lube the parts with CLP and reinstall them. Greatest hits on putting parts back in, Disconnector spring installs large coil side down into the trigger slot. The hammer legs install on top of the hammer pin. Now for the function test with the parts cleaned and lubed, Pull back on the CH and lock the bolt back. Hold the trigger back, and hit the bolt release to allow the unloaded bolt to crash home/into the locked position. Now slowly release the trigger, and then pull it normally it a second time to release the hammer off the trigger primary sear and strike the firing pin. The greatest hits here are the disco retaining/holding the hammer as the carrier slams home, and the slow release allowing the disco to release from the hammer and being retained by the trigger (read not slipping off the hammer's primary sear and striking the FP on reset). Also, do the B/C slam/reset test a few times. What you should be focusing on is the disco release point in regards to when the trigger is moving back forward. The disco should release the hammer when the trigger is almost all the way back to the at-rest position. If you find that the disco is releasing the hammer for reset before this point (half way forward or greater, then it's time to reset the disco. To reset the disco, start off with the upper in hand alone. With the trigger at rest, pull back on the hammer until you can get the rear hammer and disco sears as close as possible. The free gap between the two sears with the hammer being cocked back should be in the .001 to .003 range (about a hair apart). If you find that the free gap is much larger then this, then metal from the front/bottom of the disco will need to be removed to minimize this gap (read as the metal is removed from the disco as this forward/bottom point where it rest/is limited by the top of the trigger, it allows the disco to cam more forward, and retards the release/increases the holding tension of the disco to the hammer. |
Found a blown primer cup under the FCG. I assume that was the problem cause it function tested fine after being put back together. FWIW everything was copacetic w/ bushys assembly. What baffles me is that it only did it once. I figured if something was wedged in enough to cause a problem then it would do it cnsistently. C'est la vie, it works, I'm happy with that solution. Thanks everyone. Definitely "doubled", just once, and when I tore it apart I did get alot of debris frm dow in there. American Eagle ammo. Guess that explains it. I took Dano's advice and it function tested fine, so I assum |
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Blown primer pieces under the trigger can cause all kinds of problems. Myself, I once had a rig go runaway for the full mag (20 plus rounds), and yes, my finger was not on the trigger when the rifle went auto mag dump/bucking Bronco. But on the positive note, the bolt did lock back on the last round out, so at least the B/C stroke was cycling correctly.  |
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Hey Folks, I hope this helps. I found this info in a Army Field manual on the M16A1, dated 1974. Here it is word for word (a) Firing two rounds on a single trigger pull in semiautomatic mode. "The firing of two rounds on a single trigger pull in the semiautomatic mode is often due to the trigger pin backing out from engagement on one side or the other of the reciever. Loosening of the trigger pin in turn is due usually to a broken or incorrectly assembled hammer spring ( fig 2-52). ...." Hope this also helps, Gavin |
Good Lord! That could ruin your whole day, and everyone else's day in the vicinity. I am not sure I needed to hear that story. |
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Not the first time, nor will it be the last having a rig go south and do a runaway on me. Mac's are know for this (really open bolts when the sear gets worn), and if/when you set a rig like the 91’s/FAL's Trigger too light, you get to go for a 308 ride as well. Over time, you get used to either changing front hand positions from under the hand guard to over the top, or just grab the link to kink the feed if you have a belt feed in your hands at the time. Runaways don't scare me anymore, but it's firearm KB's you really never get use to, either by wrong reloads, or just pushing the envelope such as in the case of wildcats/uncharted territories (9mm major). |
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