RescueYou Posted June 21, 2013 Share Posted June 21, 2013 Today I was out shooting my AR, and I had 3 slam-fires. I cycled the bolt for 20-30 rounds , and every round had contact with the firing pin. The only problem that I could diagnose was it looked like I had way to much lube in the bolt/firing pin. Does anyone else have an idea what it may be? Jimmy Link to comment Share on other sites More sharing options...
a.roberts Posted June 21, 2013 Share Posted June 21, 2013 Given that the firing pin is floating it contacts every round during normal cycling and will leave a little mark on the primer. It might be too much lube or maybe brass slivers or grit that are preventing the pin from moving freely. Link to comment Share on other sites More sharing options...
Aircooled6racer Posted June 21, 2013 Share Posted June 21, 2013 Hello: High primers? Thanks, Eric Link to comment Share on other sites More sharing options...
MarkCO Posted June 21, 2013 Share Posted June 21, 2013 High primers usually get seated, not ignited. The bolt closing speed needs to be reduced to minimize the doubles. Yes, the AR firing pin floats. There are numerous combinations that can result in doubles. High bolt closing speed due to overgassing or too much spring, bagged bench shooting, even prone. I had one AR that would double here and there when benched. Some solutions...harder primers. Like move from Federals to Win or Win to CCI or CCI to 5.56 primers. Some more solutions are to turn down the gas, clip a coil off the buffer spring, go back to a standard buffer spring, get a Titanium firing pin. Link to comment Share on other sites More sharing options...
blairmckenzie1 Posted June 21, 2013 Share Posted June 21, 2013 Sounds like we need more info. Load specs? Rifle specs? Link to comment Share on other sites More sharing options...
thegunnerd Posted June 21, 2013 Share Posted June 21, 2013 Running any low mass stuff ? Link to comment Share on other sites More sharing options...
RescueYou Posted June 21, 2013 Author Share Posted June 21, 2013 Yes, running low mass stuff. JP Lo-mass BCG w/ enhanced bolt and JP silent captured spring. I run a Carbon Arms non-adjustable rifle length gas system due to the insane temperature swings here in Utah. Primers are CCI 400 and definitely are not high primers, I checked them all. With all that said, each time I had a slam fire was when I was manually closing the bolt from bolt lock. Link to comment Share on other sites More sharing options...
MickB Posted June 21, 2013 Share Posted June 21, 2013 Clean out the firing pin channel and then drop in a standard buffer and spring and try again. Sounds like too much spring, assuming your firing pin doesn't have too much protrusion.... Mick Link to comment Share on other sites More sharing options...
Griz Posted June 21, 2013 Share Posted June 21, 2013 (edited) With all that said, each time I had a slam fire was when I was manually closing the bolt from bolt lock. Given that, I would say that they are not slam fires, rather they are the hammer slipping off the sear. Probably trigger bounce from light springs or maybe a botched trigger job. I bet that if you dry fire it and hold the trigger back (keeping the hammer captured by the disconnector) when you drop the bolt it won't happen. Maybe even just holding the gun firmly against your shoulder so the trigger can't bounce will prevent it. Edited June 21, 2013 by Griz Link to comment Share on other sites More sharing options...
RescueYou Posted June 23, 2013 Author Share Posted June 23, 2013 So I shot about 300 rounds in a 3gun match today, and the problem ended up being the easiest fix. I cleaned out the firing pin channel really good and that solved the problem. Thanks everyone for you suggestions and ideas, it's much appreciated. Link to comment Share on other sites More sharing options...
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