[Jhp147]

Our dept. AR mechanic isn't available, thought I'd ask here. The weapon is a Colt AR, recent A3 type, 30 round GI mag. An officer who used an issue AR on a call the other day handed it to me to clear and put away, his hands were full. When I cleared it, I found that the round he chambered had a very light dimple on the primer, like the firing pin had gone forward and VERY lightly hit the primer when the weapon was charged. I aint no gunsmith, but this looked odd, and I have never noticed it before in my limited exposure to this gun. Cause? AD when charging likely or possible? Normal?
Thanks.

 

[6285108]

Our dept. AR mechanic isn't available, thought I'd ask here. The weapon is a Colt AR, recent A3 type, 30 round GI mag. An officer who used an issue AR on a call the other day handed it to me to clear and put away, his hands were full. When I cleared it, I found that the round he chambered had a very light dimple on the primer, like the firing pin had gone forward and VERY lightly hit the primer when the weapon was charged. I aint no gunsmith, but this looked odd, and I have never noticed it before in my limited exposure to this gun. Cause? AD when charging likely or possible? Normal?
Thanks.

Situation normal, when a round is chambered the firing pin goes slightly forward but not enough to ignite hard rifle primers. Carry on.

 

[EX CATM]

Situation normal, when a round is chambered the firing pin goes slightly forward but not enough to ignite hard rifle primers. Carry on.

+1

 

[reminton]

I also agree with the additional comment that a tintanium firing pin will cure this. They are lighter and will stop this.

 

[Jhp147]

thank you

Thank you for the quick answers,...looks unanimous.

 

[alexnormand]

The firing pin in an AR-15 rifle is "floating", if you ever took a bolt apart, you probably noticed there isn't any spring putting rearward (or return) pressure on the FP. It's just the way it's designed. When the bolt slams forward, the FP has inertia, and what will stop it is it's contact on the primer. Every AR is like this. With relatively soft primers you might notice a very light dimple, it's no problem.

Alex.

 

[Jhp147]

oh yeah

The firing pin in an AR-15 rifle is "floating", if you ever took a bolt apart, you probably noticed there isn't any spring putting rearward (or return) pressure on the FP.

Now that you mention it, I have stripped AR bolts for cleaning several times but forgot there isn't even a spring...just the little piece inserted and turned (don't have the book handy, yall know what I mean) and things held in place with the cotter pin. Makes sense, along with the other info.

 

[Just Me]

Nature of the Beast


Not a problem

 

[TXAGGIECHL]

So is there any way to accidentally set off a round that has been chambered multiple times when the bolt slams forward?

For example, multiple loadings & unloadings of your home SD rifle for various reasons (e.g. removing SD ammo for a range session & then reloading the same round repeatedly)?

 

[Grunt]

I have never heard of a round going off from light primer strikes, but if your worried about it you can ride the bolt home and use the FA to fully seat the bolt if you want to.

Don't bother with a titanium firing pin.

 

[TXAGGIECHL]

No way I'd go to a Ti firing pin. I'm actually replacing the one in my Micro due to light primer strikes & springfield's lawyer-proof firing pin springs.

Ops, wrong thread

 

[cdr]

Primer Strike

I have heard but cannot verify but multiple hits by chambering the same round over and over again can cause the bullet to fire in an AR/M-4. I believe the account came from Iraq since soldiers there are constantly being asked to load and unload their rifles depending on what they are doing and where they are located. Either way, the rifle should always be pointed in a "safe" direction just in case. Again, it's probably not an issue but then again, as a LEO I rarely have to unload in this manner.

 

[gordo63]

As long as the primer is properly seated there shouldn't be a problem. I've only had one slam fire with an AR and the culprit was easily determined to be that the primer was actually sticking out a little from the pocket of a reloaded round.

 

[cdr]

Good to know

Seems to make sense. Not sure if it's the case on M855 (62 grain green tip) but my understanding is that US military primers are generally a bit harder to ignite?

 

[Miguel]

...Don't bother with a titanium firing pin.

+1 Just leave it like it is now

 

[alexnormand]

I understand that in War scenario, this might be hard to apply, but if you are to unload and reload a firearm, I would strongly advise you don't take the same bullet over and over again. Chambering ammo many times will cause the bullet to set back inside the case. On some firearm design (like the 1911) this fact is noted after less cycling of the ammo than others. The problem is pretty much present in any firearm, though. This bullet setback can cause the pressures in the rounds to go much higher than the specifications. Now imagine it's your +P+ ammo that gets to even higher pressures.

When you drop bullets on the deck, get mags dirty, or chamber ammo many times that have a chance to be uses for fighting (or competition), I would advise putting them in the "range ammo boxes", or firing them regularly if it's possible. Carrying ammo in mags that are carried around a lot is also a renouned caused for producing feeding problems. Cycle your home defense, battle and competition ammo regularly is my advice.

I've never heard of an AR igniting a primer by releasing the bolt. I do have witnessed some very very light dimples on reloaded ammo using Federal soft primers.

Go shoot!!!

Alex.