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AR15.COM
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3/27/2016 7:24:24 PM EDT
I recently put together my first AR-15 from a Bushmaster lower and a Palmetto State M4 upper and LPK. I've had several different kinds of ammo ran through this and between 1 and 5 rounds out of every mag don't go off when I pull the trigger. When I look at the round it has a dimpled primer but it never went off. I've tried Remington, American Eagle, PMC, IMI, all sorts of ammo and had the same problem. I cleaned the bolt (and whole gun) again incase I missed some cosmoline when I cleaned it the first time. Tried it again, Same thing. Pulled the bolt apart again and polished out the bolt where the firing pin goes through, same thing. I checked firing pin protrusion and it is within spec. I'm down to trying a new hammer spring but it fires 90% of the rounds I put through it.

I'm lost. Anyone have any ideas?

Thanks in advance!
3/27/2016 7:35:59 PM EDT
[#1]
Hammer spring installed incorrectly ?
3/27/2016 7:58:15 PM EDT
[#2]
Well I'll be (insert preferred expletive) I googled "AR-15 Hammer Spring Installation" Turns out I had mine in upside down....... I will give an update when I test fire it.

If it works, YOU'RE THE MAN!!!! This has been bugging me for a while!
3/27/2016 8:02:36 PM EDT
[#3]
AR Sponsor