I think i had an unintentional bumpfire.

AR-15 » Troubleshooting

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[ARCHIVED THREAD] - I think i had an unintentional bumpfire.

Posted: 2/17/2006 10:25:56 AM EDT

I have a DPMS parts gun about12 years old that i sbr'd a few months back and has a colt 4 position stock w/an H buffer. I did a 15 minute trigger job about 2.5 years ago with good results. But the other day after about 150 rounds w/4 shots left in a 30 rnd mag it doubled. That never happened before, i did a quick check and shot the last 2 rounds and went home. At home i checked everything and all is ok (disconnecter spring etc.).

The best i can see was that i had a bump fire, i'd rather that not happen again so what would be the best modification to make. I'm thinking of filing the front bottom of the disconnecter for more contact. Any opinions?

Posted: 2/17/2006 11:13:02 AM EDT

[#1]

The double could have come from a bump, or from some debris wedged under the front of the disc for a round.

Before adjusting anything, lower the hammer down to align the sears and check the free gap between the disco-hammer sears (trigger at rest). Ideally, you want around a .003 free gap clearance and if you find that you have more than this, then as you pointed out, removing material from the front/bottom edge will retard the release and bring the gap down for that just before trigger at rest release.

Note: I have a jig/stone to do this, but if you free hand it, make sure to maintain the correct hammer top edge contact angle.

Posted: 2/18/2006 6:34:59 AM EDT

[#2]

I checked the gap looks to be about .005 so I'll take a little off. Next time i shoot i'll check to see if it bumps too easy and go from there. Thanks Dano.

Posted: 2/18/2006 12:00:09 PM EDT

[#3]

Sounds like the gap was close enough and it may just be time for a rebuild if the parts are worn (high round count), or at least a New Disconnector spring is yours is failing/worn out.

As stated above, could have just been a piece of debris in the FCG, but if it starts to double more than an "once in blue moon freak event", it’s time to break the weapon down and service it.

[ARCHIVED THREAD] - I think i had an unintentional bumpfire.

AR-15 » Troubleshooting

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