Why doesn't the AR-15 have a firing pin spring?


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DannyinJapan
February 20, 2010, 04:36 PM
I am curious as to why this is, since many other 556 rifles do...

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Supertac45
February 20, 2010, 05:09 PM
It doesn't need one; however, it is possible to have a slam fire as a result with a soft primer.

mljdeckard
February 20, 2010, 05:12 PM
The firing pin is very lightweight, and while I have HEARD of slamfires, I have never seen one. (The slamfires I heard of were with very worn weapons in training units.)

MrCleanOK
February 20, 2010, 06:18 PM
While the firing pin will leave a dimple on the surface of the primer, it doesn't have enough inertia from closing the bolt to ignite the primer. Take a pretty hefty whack from the hammer to set a round off.

jpwilly
February 20, 2010, 06:25 PM
Yes, but wouldn't a small spring help prevent those rare slam fires anyway. I've pondered this myself.

R.W.Dale
February 20, 2010, 06:29 PM
Just because there's a spring doesn't rule out all possibility of having a slamfire. There are other ways to create a slamfire besides firing pin inerta alone.

Besides where would you put a spring in the as already crowded and busy bolt assy?

jpwilly
February 20, 2010, 06:30 PM
^^^ true but you could eliminate most of them with a spring. Even soft primers wouldn't be an issue, high primers maybe...

Canuck-IL
February 20, 2010, 06:31 PM
A firing pin spring would also create one more point of potential failure between breaks that jam it and fouling that retards it.
/Bryan

benEzra
February 20, 2010, 06:47 PM
The firing pin channel of an AR would be a tough environment for a thin-wire spring, due to the direct impingement design; the bolt and bolt carrier run hotter than most rifles.

FWIW, the Ruger mini-14 doesn't have a firing pin spring, either, unless I am remembering incorrectly.

The only Title 1 semiauto that I've ever heard references to slamfiring is the SKS, and that only because (1) they sometimes come with 40-year-old cosmoline in the firing pin channel that has the consistency of glue, and (2) the firing pin channel is tapered and so is the firing pin, potentially causing it to bind in the forward position of the conditions are right. The AR, AK, mini-14, etc. are not subject to those factors, and even with the SKS slamfires are exceedingly unlikely if you use ammunition with the correct primers.

winknplink
February 20, 2010, 06:53 PM
^^^ true but you could eliminate most of them with a spring. Even soft primers wouldn't be an issue, high primers maybe...

I can't decide if you are looking for a non-existent problem, or looking to solve a next to near non-existent problem. The design of this rifle is half a century old. I'm sure the real-life necessity for such an item would have presented itself by now.

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