AR Guru's quick question

SouthernBeau · Feb 22, 2011

I'm fairly new to the AR game and was out at a buddys place sighting in my new Aimpoint. Fire two make adjustments etc etc etc.... At one point I went to put the rifle down and before i did I dropped the mag and and ejected the round in the chamber. After getting myself adjusted at the bench I grabbed the ejected round to reinsert it into the magazine, and upon closer inspection or the round i saw that there was a fairly light (but obvious) strike on the primer. That didnt sit well so to check i chambered and ejected another round and got the same result. I'm now worried about getting a slam fire and want to know if this is common with some or any AR's or if I'm worrying over nothing?

Joshua

Red Hat · Feb 22, 2011

You can get light strikes on the primer on an AR. The firing pin is free traveling since there is no spring to keep it to the rear of the bolt. Inertia from the Bolt Carrier slamming forward causes the firing pin to hit the primer lightly. There's nothing to worry about.

Midnight Raver · Feb 23, 2011

That's good to know, I would be all paranoid and take the rifle back if a rifle I had bought did that!!! Great Q/A thread SouthernBeau and Red Hat, knowledge about things like this gets valuable mileage.

SouthernBeau · Feb 23, 2011

Red Hat said:
You can get light strikes on the primer on an AR. The firing pin is free traveling since there is no spring to keep it to the rear of the bolt. Inertia from the Bolt Carrier slamming forward causes the firing pin to hit the primer lightly. There's nothing to worry about.

Ok that's kinda what I was leaning towards after I disassembled the rifle it was clear that the pin was free traveling. I was thinking that it could "cure" this issue with a Titanium firing pin less weight resulting in less inertia? Am I on to something here or should I just "shut up and go shooting"??

Clicker · Feb 23, 2011

Don't waste your money on a fancy firing pin just keep shooting!

Red Hat · Feb 24, 2011

Clicker said:
Don't waste your money on a fancy firing pin just keep shooting!

Exactly! The AR platform has been around since 1963 and there are millions out there. If the firing pin caused any problems it would have been changed years ago.

Nato · Mar 20, 2011

I hate to be a "mildly dissenting" voice here, but there is one thing that I think must be said. This is not typically a problem, however it is something to be aware of. The light tap of the pin can (under certain circumstances), fire off a round. This typically happens when ammunition that uses an extremely light primers (certain types of Winchester hunting ammo are known for this). Basically stick to the normal AR-15 food (federal bulk packs, most any FMJ ammo) and you are fine.

This issue is more pronounced on older designs of military rifles, which tend to use much larger and heavier (almost mauserish) firing pins.