M1a kb! ??

T

twoblink

New member
Reading from another (yet what a shock...not) Glock Kb! thread, someone mentioned that a bolt slide slam might fire in an M1A? Really? I assumed that the firing pin is not free floating like say an SKS, and that a disconnect exists so the tail of the firing pin cannot slam into the primer, unless in full battery?

Am I wrong or what??? As an M1A owner, I'd like to know!

Please people, just the facts, no FUD.

Albert
 
Yeah, I heard about that too so I read up on it. The deal is, you're chances of it happening are like getting struck by lightning. Others could give you all the technical info...
 
Albert,

I have emailed you an article from american rifleman regarding M1A slamfires. It was sent to me with my M1A..if any one else would like a copy, please email me at

bob_8251@hotmail.com

it is 6 pages long so may take a while to download...i scanned it in .jpg format so anyone should be able to open it up.

bob
 
OK, I read the article that Bob sent to me, thanks Bob.

I just (of course) right after reading the article, put in a few rounds, and slammed the bolt, and took a look.

Indeed, there is a very small dent against the primer from the slam, but it was a seriously light strike, from probably the weight of the firing pin itself, no hammer behind it. I could see this going off if the primer was sensitive, but it would have to be SERIOUSLY sensitive (wait, squirrels... Damn, they ran away before I can shoot a few more soft pellets at them) anyway.. The other thing would be if the firing pin got wedged when it was out, or debris on the bolt face. All these things can happen (I guess) but it would be rare. I think it's a primer issue.

But now I'm away of it (not that I don't) bit I'll take extra care when I rack one on my M1A next time...

Albert
 
BobR, you beat me to it. Correct me if I am wrong, but the upshot of that American Rifleman article is that you need to load an M1A / M14 using the magazine and not load a round by hand.
 
Range incident

New M1A.Was loading 5 rds thru mag-caught the op rod with my left hand as bolt slammed home. Didnt notice. pulled trigger. Nothing. 30 sec later opened action. failed to fully close on the round.no strike, otherwise dangerous kb from an out of battery status. lesson learned-keep hands off op rod when chambering,load only from mag. Outstanding weapon.
 
I have a hard copy of an article titled "The Mysterious SLAM-FIRE" that was a reprint from American Rifleman. It may be the same thing as BobR has.....If you want a hard copy I can mail or you can down load and see which one is faster :rolleyes: 2 hours or 10 days using the USPO...ya gotta love em though, penny increase every quarter and 2 days added to delivery time :confused:

Karsten
 
The M1/M14 design has a bridge across the receiver which keeps the firing pin from moving forward until the bolt is turned to the locked position. In some clones, this bridge is not properly made and in some "cut-and-weld" receivers, the receiver length has been shortened enough to partially negate the safety feature. Anyone having a rifle of that type, original or clone, should check that safety feature to be sure it is operational.

Even with the block as described, a fast moving bolt can impart enough momentum to the firing pin that it will still mark a primer slightly. This has no effect on military primers, which are hard, but in theory could ignite a soft primer.

The M1/M14 has no firing pin spring.

Jim
 
M1A KB's

Most, if not all i have ever heard of, come from IMPROPER primer seating.........
Using commercial primers(which are softer than mil spec), you have 1 strike against you already.........however,
They ARE totally safe IF.................they are seated slightly below the bottom of the case primer pocket........IF you can run your finger over the primer, and feel it in ANY way ABOVE the primer pocket........DO NOT attempt to shoot it in an M1A............:eek:
 
I also wouldn't try to shoot it in an M1 Garand or an AR-15.

In point of fact, if the primer isn't seated properly, it's probably not a good idea to try to shoot it in anything, although a revolver probably is pretty safe. :)
 
Primers for any cartridge should be seated to 0.005" +/- 0.002" below the case head.

IF there is a remote chance of a KB in an M1A it would probably be with Federal primers. They are about the softest. But, seated properly, even they should not present a problem.
 
The only actual kb that I know of in an M1A received a lot of publicity (and a lot of "not so expert" analysis about 6 months ago. The cause was determined to be a split "no name" barrel, and not the fault of the receiver, although the receiver was destroyed.

Slam firing with a locked bolt will not cause a kb. Only premature firing before the bolt is locked will do that, and that is a rare situation indeed.

Jim
 
Here's a fun thought: chambering rounds in your rifle while checking out a slam fire question. Were you, like, inside your den when you were doing this? Just curious. I once meet a gent who had an interesting experience with an old Chinese SKS. It's amazing how much lath and plaster, and couch, and oak flooring that the little ol' 7.62x39 can penetrate. The gent also reports that it got sorta LOUD inside that little bedroom. Stay safe.
 
It's not just M1As, it's also M1s.

The after-action photos I've seen show signs of the round firing when fully chambered, but the bolt is apparently about halfway rotated to the locked position.

Geometrically, this means that the bolt has rotated just enough to let the tail of the firing pin *start* to clear the camming surface which retracts the firing pin as the bolt unlocks.

There are reports that the M1 firing pin has a flat side because of a demonstrated need (in early 1937?) to reduce its weight....precisely to prevent the types of slam-fires which I've seen reported with reloaded ammo over the last 20 years.

However, an NRA article I read in the '80s (same one, gents?) reported a profound inability to induce any slam-fire without having both a high primer and some ball powder in the primer pocket. Ordinary high primers just got seated as the bolt slammed home. Perhaps the ignition time could allow the bolt to rotate halfway closed before the pressure opens up the locking system???

Or maybe it's just the statistically improbable but maybe demonstrated situation that with commercial primers, that tiny little firing pin rattle could set off one primer in a million.

Made me nervous enough to use only CCI primers.

I've heard Winchester are also hard enough, compared to the Federals that those Match Rifle shooters were using in their Service Rifles....
 
For those who are concerned, I think they still sell titanium firing pins which are very light. Check Brownells.

Jim
 
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