Originally Posted by jlloyd73
I have an AR-15 that will sometimes shoot a double burst. .
I've seen a few ARs that fire 2 shot bursts. Sounds like yours only fires 2 rds, not 3 or more. If this is the case the first place I'd look is at the hammer, disconnector and trigger timing.
If the disconnector hook doesn't hold the hammer back after the first shot till the trigger ledge can lock into the bottom of the hammer, it would be the sear area on most arms, the weapon will fire a second shot when the trigger is released.
When you pull the trigger it fires, when you ease off on the trigger it fires again. With a normal trigger pull this can happen so fast it feels like full auto for 2 rds.
An easy way to troubleshoot this is to (A) pop out the takedown pin and pivot the upper down to allow access to the lower FCG parts.
(B) Grip the hammer & pull the trigger, don't release the trigger yet! (C) The hammer will fall forward, now with the trigger still pulled, push the hammer back till the disconnector hook locks the hammer back.
(D) Now if there is a problem when you release the trigger, the hammer will fall again, (second shot on one trigger pull).
Now that the trigger is released, push the hammer back again, the trigger notch catches the hammer and everything is normal untill you pull the trigger again. Thats why it will only fire 2 shots and stop.
I'm not saying this is your problem, but it is the first place I'd check. If all is OK in this area then you can rule it out. I've seen this situation caused by parts wear, out of spec FCG parts and even out of spec lowers.
As far as a legal problem, I think so, but WHY take the chance? When the lawyers get involved, common sense goes out the window. Also if you would have the condition described above, the shooter fires one rd. If the shooter still has the trigger pulled and turns the weapon your way, when he releases the trigger its gonna fire again!
Good luck solving your problem, Ken