AR-15- Firing pin/safety problem?


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LkWinnipesaukee
December 25, 2006, 04:24 PM
Hey guys,

I loaded then unloaded a round into my new AR and when I picked up the cartridge, I noticed the primer had been punched a fraction of an inch. I took the bolt assembly out and was able to manipulate it so the firing pin stuck out the same fraction of an inch.

Is this any cause for concern? I dont believe the firing pin should strike the primer unless the trigger is pulled.

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ocabj
December 25, 2006, 04:26 PM
Free floating firing pin. Normal on the M1, M14, and M16 platforms as well as other semi-automatic rifles.

LkWinnipesaukee
December 25, 2006, 04:35 PM
Is it dangerous?

rbernie
December 25, 2006, 04:47 PM
Only if you use very soft primers and/or have a very dirty firing pin channel that causes the pin to 'stick' in the forward position.

I've shot lots of commercial and MilSurp 223/5.56 NATO and never had an AD as a result of the free floating firing pin.

hagar
December 25, 2006, 04:48 PM
Yes, it is dangerous if you use Winchester small rifle primers or commercial 223 ammo. Use Remington 7 1/2 or CCI primers and you should be ok. I still would not recommend you do it indoors, or often. I have seen enough AR15 slamfires on the highpower range to realize it is a common problem. Every time I see a slamfire I ask the shooter what primers he was using. The answer always is: Winchester.

ocabj
December 25, 2006, 05:17 PM
I use Winchester SR primers in my .223 service rifle practice ammo. I also use Winchester primers in my Garand reloads. Never had a slam fire.

Of course, in the event you do have a slam fire, it shouldn't be a dangerous situation in the sense that you should always have the muzzle pointed in a safe direction when you close the bolt.

That said, my only problem with Winchester primers is that they are not very good at holding up to the AR pressures. I've had the cups pop out of hot NATO pressure handloads and I've had a weird primer piercing with Winchester SR primers in even mild loads.

I use CCI BR4s for my competition handloads.

LkWinnipesaukee
December 25, 2006, 06:51 PM
Ohh jeez. I havent even checked the firing pin (or shot it yet). And I was chambering Wolf ammo.

MisterPX
December 25, 2006, 07:02 PM
Not an issue on factory ammo, neither is free floated pins. Most semi's have free floated pins.

sacp81170a
December 25, 2006, 07:07 PM
I loaded then unloaded a round into my new AR and when I picked up the cartridge, I noticed the primer had been punched a fraction of an inch.

Yep, standard with M1A, AR, M-14, Garand, etc. It's one reason you should never chamber a round until you're ready to shoot. Given the right (or should I say wrong?) set of circumstances, it's possible for the primer on a chambered round to be struck and detonated by the firing pin (on an M-16, at least) even with the safety on. Nothing wrong with the weapon, that's the way it was designed.

For that matter, milspec 1911's are the same way. They can fire when dropped with a round in the chamber because the firing pin floats free. More modern designs like Kimber and Para incorporate a firing pin block, but a plain Jane 1911, well, just don't drop it. :D

Zak Smith
December 25, 2006, 07:30 PM
re: no firing pin spring on 1911's?

Is that true?

My Commander (Caspian), 5" (Dan Wesson Patriot), and my two SV's (2011) all have springs that hold the firing pin rearward.

sacp81170a
December 25, 2006, 07:36 PM
re: no firing pin spring on 1911's?

There's a firing pin spring alright, it just doesn't keep the firing pin from going forward given a sharp impact. I've got an SA Target model and they specifically say the way they overcome this problem without using a firing pin block is to use a titanium firing pin. The titanium is lighter than a steel firing pin and so has less mass to hit the primer with if there is an accidental impact.

I'm still not sure I trust it without a firing pin block, though, so I don't use it for concealed or duty carry. I'm not sure how big of a risk this is, but knowing Murphy and his law...

I would imagine that the greatest likelihood of an AD would be if you had a weak or worn firing pin spring. Still, I took apart a Para once(never again) without realizing it had a firing pin block. Had to get a gunsmith friend to help me put it back together correctly. :uhoh:

He's the one who pointed out why they included a firing pin block in their design in the first place.

Dienekes
December 25, 2006, 07:44 PM
As mentioned, normal in M1, M14/M1A and M16/AR15s. As long as everything is in spec all is well. Have been shooting multiples all three types of rifle a long time and while all dimple none have set off a round yet. Could it happen? Yes. that's why muzzle control is important.

Quality control is important when reloading for these, particularly seating depth on primers. These things are not your father's sporterized Mauser.

As to WSR primers, I use them routinely with no problems.

Nhsport
December 25, 2006, 08:38 PM
To be clear here:

This is generally not an area of concern with factory ammo and a firearm that is well maintained (clean)


Standard practise is to only drop the bolt on live ammo with gun pointed in a safe direction.

Any time one puts ammo in a firearm it isn't something to be taken for granted

Redhat
December 25, 2006, 11:27 PM
MIght also want to make sure your firing pin protrusion gage is a go!

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