Are slam fires common in an AR?

[Sinclair]

When I was much younger and uninformed about firearms I put a round in the chamber and dropped the bolt and bang it fired. Wasn't ever really sure if it was a slam fire or some other malfunction in the fire control group. I have had people say an AR will not slam fire but it seems others have experienced it.

The problem with you guys building from a "kit" of parts acquired from various venders is that cross platform compatibility can be hit or miss. A genuine slam fire happens when the inertia of the firing pin is sufficient to activate the primer. Many years ago, I built a FAL from parts I acquired from various surplus houses. I had two sets, one legal and the other illegal. Because I had been told the the FAL was notorious for slam fires, so one day I disassembled the trigger group and installed the illegal parts. Did the two round test and yes the primer was dented, but the second round did not fire. After many attempts, I concluded that maybe there were other causes for the apparent slam fires that others had. Actually, the dent did not appear be any larger than from the firing pin alone with the legal parts.

My Father had a Colt 1911 that had been accurized and if you released the hold back latch and let the slide go forward under spring pressure on a chambered round, it would go full auto firing several rounds before it stopped. Bad gunsmithing! The jar of the unopposed slide slamming to a stop caused the hammer to slip of off the sear. Exciting, but not actually a slam fire. What I am saying is that IF an AR can or does seem to slam fire, the problem might be in the trigger group being out of whack.

Since there are so many heavy thinkers on this forum, I wanted to inject my 2 cents worth as something for you all to think about.

[Klem]

the problem might be in the trigger group being out of whack.

I agree.

I had a Glock 19 with an after market Ghost trigger. You file down the stub on the disconnector until the gun fires. That way there is no overtravel typical in a factory trigger. But if you do it fine enough and don't hold the frame tight the gun full autos as it resets into your finger. It's good fun after the first heart attack.

All down to the trigger.

[FLshooter]

I never had a slam fire in an AR 15. And I have known anyone who has. But a while back, at my local gun club, And older guy had an SK rifle slam fire on him. He wasn’t holding it tight while he was bench rest shooting .It got away from him and shot him twice in the back. Blamed it on high primers.

[Klem]

FL,

Brutal...How did he end up?

[GoneHiking]

They're not common, but they do happen. One of the guys in our High Power matches had one last summer in the slow fire prone stage, where cartridges are singly loaded. You're particularly vulnerable to a slam fire when single loading like that since the cartridge isn't being stripped from the magazine and there's no resistance to slow the bolt carrier down. Many High Power shooters avoid using soft primers, like Federal, for this reason, preferring hard ones, like CCI #41s instead.

[Old Bob]

I also use CCI #41 primers when I reload for all my AR ammo (5.56mm, 7.62x40WT & 22 Nosler). I use CCI #34 when I reload for my M1A & Garand. I have a mix of primer brands for my bolt & single shot rifles... all the standard variety.

[FLshooter]

FL,

Brutal...How did he end up?

https://www.floridatoday.com/story/news/.../100388180

[SDW]

I've had it happen in the form of a double-fire. As in full-auto for two rounds. It happened to me once with my old Colt SP-1 and also once with my Remington Model 8.

[ported45]

One of these days when I have nothing to do, I am going to sit at the range and keep feeding a 223 round with a CCI 400 primer into the AR over and over again to see if it will ever slam fire when picked up out of the magazine. All I ever see is just the faintest dimple in the primer when it is extracted without being fired.

Being use to single-feeding a bolt gun, when I got my first AR I was shooting 300 BLK and for some reason had single-fed a round all the way into the chamber. When I hit the bolt release, the bullet hit the 100 yard berm. Thank God I was using the Lead Sled, so it was already pointing at the target. I have single-fed a few since then, but I never go as far as getting the case into the chamber and have never had a slam-fire since. I owe that lesson to being unfamiliar with the AR firing system.

[FLshooter]

I think the ammo used by the man who shot himself was NATO rounds he picked up on the cheap.God only knows how old they were. Probably post Vietnam war era.

[Lastrites]

I would imagine one would have more of a chance with a grendel if you inadvertently placed a standard/normal length firing pin into one of the short bolts that have been on the market for the past several years. Never seen one myself, seen more than several rifles do some doubling though.