M14 Firing pin Tangs

[RDS]

Why is it that most SAI M1As have firing pin tangs that are chewed up but you hardy ever see an GI M1 Garand with a chewed up firing pin tang? It is the safety bridge is not milled to spec on some M1As.

[m14brian]

It is the safety bridge is not milled to spec on some M1As.

As well as on some other commercial manufacturer's "M14" receivers.
m14brian

[Moorem1s]

Just thinking about and discovered an sai firing pin like this today. Really the first time I gave the receiver a "hard look" after having it for about 10 years. It's an early 5 digit and honestly, I'm not thrilled with it.

[m14brian]

Huh, the early ones in that range fall in the so called "Golden Era" of M1As. They were better to spec than the later ones.

Mine are in the 129,xxx and 145,xxx range 4 line receivers and seem mostly to be in good spec, no bolt roller defect, perfect looking op rod track, etc.
m14brian

[Moorem1s]

M14brian, yep, one of the "Golden Era" guns. I was trolling thru Tonyben's videos yesterday and came across the bolt roller defect. First I'd heard of it, and mine has a small case of brd-Enough to keep the bolt from completing locking all the way down. I also noticed, shame on me for not realizng this in the 10 years I've owned it, only the right locking lug is making contact on lockup! So I'll shorten headspace by fixing brd, and lose my gain plus by lapping the bolt down. It's been a great, accurate rifle, and apparently a danger to shoot. I had a couple issues shooting the atomic ammo, so I was investigating causes/ damage. The brass failed at the rim- if you go to ammo section at cmp forums and view the atomic ammo, you will see the failures I'm talking about.

As as far as the atomic ammo, my investigations conclude a primary issue of loading with Varget in once fired brass. I do feel that Varget is just a touch too slow for the M1a specifically , and the shell is already being pulled on by the bolt before the complete combustion in the shell has taken place. A second issue could be that my two failures of brass were due to being shot from a machine gun?

So, back to the receiver checkout. Brd;then I notice left locking lug area improperly machined. I picked up a Bula bolt at Perry last year thinking I could close some headspace, well, the bolt won't close up once installed. It has a GI bolt in it currently. Two strikes so far. I keep inspecting and see what appears to be a crack on the heal from the underside. Luckily, it's not a crack, just a line left from the casting. I'll try to get som pictures up soon. Lastly, the firing pin tang is chewed to bits, so I look at the receiver and see the corresponding area on the receiver is poorly machined causing the chewed pin tang.

[RDS]

Some early guns are better than others. Guns over appox. 35XXX to appox 95XXX seem to have less problems. Check out Lee Emerson's books. He goes over the changes made to SAI receivers and appox. serial range made. The thickness of the receiver heels was increased several times to prevent heels from cracking. Devine Texas guns have the thinnest heels. A long time ago I sold off all my Devine Texas guns with out any regrets.

[m14brian]

When you start getting into the slower burning powders, that is when you need a Schuster gas plug to bleed off a bit of it, for heavy bullets also. Slow burning powders can also snap an op rod too.
m14brian

[RDS]

Myself I have never used any powders slower then WW748 or IMR 4895 in M1A or M1 Garand.

[Moorem1s]

My experience with this Atomic ammo is an eye-opener. I will chose to never reload anything slower than IMR4895 in an M1a either, contrary to others' experience and wisdom.

[RDS]

I read somewhere a few years back not to use chrome firing pins in SAI M1As. The reason being that the chrome firing pin tang would wear the safety bridge. The thought was better to have the standard blued firing pin tang wear than the safety bridge.

[RAMMONT]

As as far as the atomic ammo, my investigations conclude a primary issue of loading with Varget in once fired brass. I do feel that Varget is just a touch too slow for the M1a specifically , and the shell is already being pulled on by the bolt before the complete explosion in the shell has taken place. A second issue could be that my two failures of brass were due to being shot from a machine gun?

Not to hijack the thread but I don't understand your comment about the case being extracted before the "complete explosion" (I assume you mean before the powder burns completely since the powder doesn't explode). In actual fact the powders that work best rarely burn 100% by the time the bullet exits the bore (which happens well before extraction starts).

[RAMMONT]

Steel banging on steel will always cause deformities, I'd rather have a cheap firing pin tang get beat up than an expensive receiver bridge. If the receiver bridge is milled and hardened properly then it should not become deformed over time, the firing pin tang should be the part that wears and will subsequently be replaced.

[Moorem1s]

Rammont, no worries. I meant combustion-not explosion. I've decided to pull and reload all my atomic ammo regardless. Thanks for the correction.