7.62 NATO loads for M1916 Spanish Mauser

[GunsNotPuns]

No, no, I'm not going to start a 7.62 NATO/.308 Win argument -- I'm curious if anyone has loaded for the M1916 Spanish Mauser chambered in 7.62x51mm.

We've all heard the stories that the M1916s in 7.62 NATO are grenades waiting to go off thanks to the two lug system and (if you shoot commercial ammo out of it) the higher pressures of .308 Win -- though I've never heard/read a single first or second person account. Anyway, long preamble to essentially ask has anyone loaded specifically for this rifle to account for its allegedly lower capability?

The recipe I want to gin up involves 150 gn bullets and BL-(2) since I have access to cheap plenty of the former and a lot of the later on my shelves. Any suggestions from the hive mind? Personally I think the concerns over this rifle are nonsense, unless the Spanish Civil Guard had a built in tolerance for its members being killed by their own rifles, but doing some due diligence is never a bad thing.

 

[OneBarfly]

I had one that I reloaded for, reducing them so much that the extracted rounds were sooty and the primers started backing out. Afterwards, I examined the spent casings and they were all seriously out of round, being bulged out on one side of the case. So, the chamber was seriously fooked. My guess is that someone in the past shot full-strength .308 or 7.62x51 out of it, buggering the chamber. Sad, as the rifle was minty otherwise. Sold it for parts to a gunsmith, providing full disclosure. While the 93/95 action is strong, I don't think that these Spaniards are up to a diet of full-strength modern loads of NATO 7.62x51. Stick with something equivalent to the original 7.62×51mm CETME load.

 

[Hitzy]

The rifle can handle the pressure, it can't handle escaping gas from case failure very well.

 

[tiriaq]

Samco International was the first US importer to bring in Spanish 7.62 rifles. They sent samples to the HP White Labs to have them tested. The Lab cleared them.

 

[Potashminer]

I just read an old Guns and Ammo article - the HP White lab had to go to 98,000 psi breech pressure to destruct those 1916 Spanish conversions submitted for testing by SAMCO. See below the cover page of the pamphlet by the Spanish regarding the conversion - you don't need much Spanish to understand it was a conversion from 7mm (in the 1950's that would be what we call a 7x57 or 7mm Spanish Mauser) to 7.62 NATO. Proofed, etc. I have one, I do not worry whatsoever about bulk Hirtenberger 7.62 or published book loads for 308 Win and 165 Speers. We do not experience the case failure like they did back in the day. And I have Go/NoGO gauges that I use after every outing - nothing is moving...

 

[Potashminer]

I had one that I reloaded for, reducing them so much that the extracted rounds were sooty and the primers started backing out. Afterwards, I examined the spent casings and they were all seriously out of round, being bulged out on one side of the case. So, the chamber was seriously fooked. My guess is that someone in the past shot full-strength .308 or 7.62x51 out of it, buggering the chamber. Sad, as the rifle was minty otherwise. Sold it for parts to a gunsmith, providing full disclosure. While the 93/95 action is strong, I don't think that these Spaniards are up to a diet of full-strength modern loads of NATO 7.62x51. Stick with something equivalent to the original 7.62×51mm CETME load.

I am total newbie to this. Are you saying that using "full power" (let's say excessive pressure) loads altered the chamber dimensions? I have seen bolt lug set back into softer receivers, but I have never seen a chamber "buggered" other than when it let go - i.e. cracked. Can you tell me more about this? As well, all the documentation that I can find says that the CETME was a semi-auto rifle for which "reduced" loads were required - the Guardia conversions were to 7.62 NATO - see my above post.

 

[Ganderite]

7.62 and 308 have similar pressure limits.

The difference between the M95 and the M98 is how they handle the gas from a blown case.

I have used M95 actions to make 308's and 7-08s. The ammo I load for them is 2 grains less than I would use in a better action.

Although I would shoot 7.62 or 308 commercial ammo in a M95 (M93) I would not shoot old crusty ammo.

 

[OneBarfly]

I am total newbie to this. Are you saying that using "full power" (let's say excessive pressure) loads altered the chamber dimensions? I have seen bolt lug set back into softer receivers, but I have never seen a chamber "buggered"

I know what I experienced, I can't say for certain how it happened, nor did I claim to, rather it was conjecture on my part; however, the chamber was out of round. Shoot full pressure rounds if you like: Your rifle, your decision.

 

[Hitzy]

I know what I experienced, I can't say for certain how it happened, nor did I claim to, rather it was conjecture on my part; however, the chamber was out of round. Shoot full pressure rounds if you like: Your rifle, your decision.

Probably just an oversized chamber, the cartridge sits on the bottom and when fired expands unevenly. Very common occurrence in 303's milsurp rifles as well, not really any kind of safety concern.
I stick to neck sizing in old milsurps to avoid over working brass which can lead to case failure.