M1A had a slam fire today. Explinations?

E

El Rojo

New member
I was shooting the M1A today and I squeezed off a shot and somehow I had a double fire. It was crazy. I was shooting through my chronograph too and I am thankful there was only one extra bullet that went down range otherwise I might have chewed up my sky screens! It was sort of exciting.

Anyway, what causes this? Is this an actual "slam fire" or is that only when the whole magazine goes until empty? I remember Springfield gave me an article on slam fires when I bought the rifle. I guess I better go read that again.

The rifle still performed fine afterward and there appears to be no problems. Just a brief moment of full auto to get me excited. By the way I was using my own 147 gr. Win FMJ/BT reloads (they chronograph at 2800 FPS). Thanks for your help.
 
Rojo,

No, what you experienced was most likely NOT a slam fire. You had a "double". This was probably caused by you not "following through" on the trigger and not having the butt firm enough against your shoulder. It's happened to me on occasion with my M1-A and my AR, both of which have match tuned triggers. This seldom happens with a stock military trigger. Nothing to worry about, as long as it does not happen regularly, then I'd have the trigger checked by a good M1-M14 smith.

A true slam fire is not something you'd enjoy. This happens when a round fires out of battery, before the bolt is fully closed. This usually results in severe damage to the firearm and possibly to the shooter as well. Not pleasant or something you'd want to repeat.

Some known causes of slam fires in M1 and M14's are:

High primer in handloaded rounds,

Chamber dirty enough to prevent the bolt from completely closing,

Worn or out of spec receiver bridge, which normally stops the firing pin from moving forward when out of battery,

Broken off firing pin "nose" (at the rear of the pin),

As for getting a multiple discharge from an M1-A (or AK, or AR, or FAL), you can do it intentionally in a parlor trick called "bumping". This is strictly a trick however, good for making noise and wasting lots of ammo. The method involves holding the weapon in such a way that you are not able to use the sights.

Swampy
 
I bought a new M1A Match some 20 years back, and the first shot (brand new, out of the box) at the benchrest it doubled.

I called SA and was told they thought it might be the disconnect or sear. They sent me a new hammer and some other pieces; I reassembled the trigger group and had no more problems.

Technically and nit-picky legally, if it will double, it's a full-auto weapon in the eyes of ATF--fix it ASAP.

FWIW, Art
 
Art, I dont see how they could call it FA if improper follow through caused it to double. I'm not knocking your concern, just that by a single function of the trigger it would be FA, but the rifle recoiling coupled with loose hold which lets the trigger reset and then accidently squeezing off a second round, would be two functions of the trigger, correct? If what you're saying is true, then all those funky trigger adapters would be illegal also.

Do a search for M1a Scout/squad doubles and read that thread, I posted this question awhile back about my friends rifle which was doing the same thing.
 
Ed4: First off, my particular M1A doubled without any accidental second pull of the trigger. It did not reset. There was some defect in the mating of the sear, hammer or disconnect. I said a few choice things such as, "Golly, gee!"; put the gun away, and called SA for replacement parts--I had already read about the problem as a "sometime event" along with warnings of slamfires before receiving the rifle. The "funky trigger adaptors" merely allow ultra-rapid movement of the trigger in semi-auto mode.

The law as written makes no provision for accidents or worn parts. If a gun fires more than one shot with one single motion of the trigger, it's a Bad Thing.

A reasonable LEO might understand about a parts problem and merely say, "Fix it." A judge might be understanding, as might a jury. However, here one is depending on the goodwill and intelligence of people.

I have read (one of Pate's articles in SOF, IIRC)--and have no way of verifying--that at least one agent of the ATF is rather expert in finding a way to handle/hold/manipulate a semi-auto weapon of the AR-15 persuasion such that it will double. He then testifies in court that the gun fired two shots from one pull of the trigger.

I know from having been on juries and from having been a witness in a couple of trials that there is that certain percentage of LEOs who regard an arrest as a scalp, a trophy. There is that certain percentage of prosecutors who care less about actual guilt or innocence than in getting a guilty verdict--the trophy, the scalp. I wanna keep my hair.

I don't think I'm paranoid so much as very, very cautious.

Okay?

Art
 
It looks like some terminology is getting confused here.

"Slam Fire," "Doubling," and "Firing Out of Battery" are different things.

Slam fire is often associated with open-bolt sub-machine guns. The bolt has a fixed firing pin, and as the bolt chambers the round, the fixed firing pin contacts the primer and fires. This can also happen with semi-auto rifles such as the M-1, M-1A, and AR-15 (among others). These rifles have floating firing pins, which upon chambering a round, can have enough inertia to contact the primer and fire. This is not firing out of battery. This problem is often addressed by using a light weight firing pin and hard primers. (The Fulton Armory web-site has a good FAQ about this).
 
It was most likely mechanical.

I had a good firm grasp of the rifle and it was firmly planted into my shoulder. It was mechanical whatever it was. It wasn't a big deal and it only happened once. I will keep an eye on it. Thanks for all of you help.
 
Threads from Lane's Tips Page.

Doubling #1

Doubling #2

Reloading Dangers

"......... The cause of a slam-fires; Remember, the Garand, the M1A, and the AR15 all have floating firing pins. That means they are not held back by a retaining spring. When you let the bolt slam home on a single-loaded cartridge, it does so with enough force to fling the firing pin forward, many times with enough force to ignite the primer. This happens before the bolt is completely closed, resulting in the bolt being slammed back with great force. I had it happen with my AR15. It blew the sides of the upper receiver outward. destroyed the bolt and bolt carrier, blew down through the magazine, destroying it. Fortunately, I was not hurt. I had the rifle repaired, then sold it. Never liked them anyway. I saw a slam-fire happen to a Garand, but no damage was done at all...... Semper Fi; Leatherneck "

-- Kernel
 
Art, Your last post brought it all into proper perspective. Knowing that it was an accident, or worn/ill-fitted parts, does nothing when you have rabid DA'a and judges around.

On that note, I would suggest sending the rifle back to SA and keeping meticulous track of the correspondence and repair paperwork.

Since this is not all that uncommon to M1A's, I'm thinking maybe I should send mine to SA to be checked out, even though its never doubled on me. Start building my defense before they even have thoughts of a case against me!

Thanks Art!:D
 
Dunno about nowadays, but my go-'round was 18 years back: When I explained that I knew how to disassemble and reassemble the trigger group, they sounded real happy to only have to send me the pieces, freebie--and not deal with shipping back and forth and all that.

FWIW, Art
 
Bump fire

Hope you don't mind if I interject a question?
From the several discriptions above, then it would be correct to say that bump fireing a weapon of any kind would be a temporary conversion to FA and therefore, Illegal.
I have a Match M1A, and when I first got it I also did not brace and follow through, resulting in a 5 shot bump fire. Thank God I was the only one on the range.
I cured it with good technique. You can bump fire any SA quite easy with practice, or in a match trigger, by accident. Now I've never had a problem with this again unless I've tried to reproduce it.
see ya'll later
DA
:D
 
Darkangel, read my lips: The law as it is written does not provide any exemption, slack nor "Time out!" for "bump fire". All I'm talking about is the law, no matter whether it's rational or not.

What folks choose to do with match triggers, etc., is not my business. Everybody is responsible for their own "risk analysis".

Scenario: A guy is at a match with his M1A; 20 entrants. A BATF guy might well be one of the competitors or spectators. A "bump fire" occurs. "Hey, guys, I got me a freebie! And do I have witnesses!"

:), Art
 
Doing the "Bump" is NOT against the law, as the weapon is only firing one round for each action of the trigger. It is just doing it very fast.

Now, perhaps my understanding of the definitions is incorrect, but "Doubling" is getting two shots for one action of the trigger. And Art is very correct that there is no exemption or slack for this as it falls under the BATF definition of fully automatic. But this is not the bump.
 
Kernel has a good point.....you might want to buy a combo tool and take the bolt apart and make sure that the firing pin has no possiblity of sticking...............fubsy.
 
Given the fact you were shooting reloads, and sound like you were using good techinique and follow through, I would bet on a slam fire.
Reloads causing this in an otherwise sound rifle with an experienced shooter makes me suspect the reloads. Not trying to impune your reloading skills but I would be concerned with that first. Especially if you have shot a bunch of factory ammo through this rifle without problems.

If your primer is seated a little high that floating firing pin may strike it with enough inertia to set it off. If it goes off after rotating into battery (bolt rotated closed) it is just a slam fire. If it isn't in battery it is an Out of Battery Explosion.

Use primers with hard cups. CCI makes a primer designed for use in miltary type(floating firing pin) semi auto's. Also, uniform all primer pockets for consistent primer seating depth. Short pocket could = high primer could = KABOOM.

Did you retrieve and examine those 2 pieces of brass? Any signs of excess pressure? case bulge or separation? Something to indicate an OBE?

Did you then shoot some factory ammo through it without problem?

Mike
 
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