Mauser 1891 Argentino Questions

[Dcoil03]

Hi everyone, First of all I'd like to introduce myself. I live in Arizona, and I've been a plinker since a senior in high school. Bought my first rifle the day I turned 18 (a Yugo SKS, though I had inherited a couple before that), and now my collection is up to 7 firearms! I've been a long time viewer of the The Firing Line forums, as many posts here have answered my questions. Thanks for having an informative forum that I've used many times in order to find the answers I was seeking.

That being said, here's a couple of new questions that need answering!

One of the rifles I inherited was a Modelo Mauser Argentino 1891. It has a sporter wood stock, iron sights, matching serials on the receiver, stock, and what I'm assuming is the rear of the barrel (just behind the rear sight, stamped just in front of the receiver number) of F 4XXX. The bolt however, is not the straight bolt originally on the rifle, but rather a wide turn down bolt with a different serial (F 2XXX). The front site seems a bit tweaked, in that it's not parallel with the barrel.

What puzzles me about the rifle is that "cal .308" is stamped on top of the receiver. I know the rifle is usually chambered for 7.65 Argentine, and I had assumed the rifle had been rechambered by my late step dad. Since I was a neophyte at firearms, I loaded it with .308 Winchester rounds and fired away. It always shot up and to the left, and I had assumed it was because of the site, but tonight the thought hit me: What if it wasn't rechambered for .308 Winchester? Could I have been firing unsafely based off an assumption I made of a stamping on the receiver and have thus far only been lucky?

I had been considering selling the rifle since I don't shoot it that often: I already have another rifle chambered (for sure) in .308 winchester and usually prefer to take that out. Based on all this, is it worth keeping?

[Buzzcook]

It is a mistake to fire any rifle when you aren't sure of the cartridge type.
For older surplus rifles you should have the head space checked to make sure it if safe to fire, even if you are sure of what ammo it uses.

It is likely that your 1891 was re-barreled as a .308, but better safe than picking metal fragments out of your face.

Sorry to say your rifle probably isn't worth much.

[sc928porsche]

You should take the rifle to a gunsmith and have it chambercast, have the barrel slugged, and of course once the cartridge has been identified, have the headspace checked.

[Slamfire]

but tonight the thought hit me: What if it wasn't rechambered for .308 Winchester? Could I have been firing unsafely based off an assumption I made of a stamping on the receiver and have thus far only been lucky

It never hurts to have an expert opinion. And the advise to look before you leap is timeless.

There are a lot of rifles out there, which have been rechambered, and no stamping exists on the receiver. I made one. It is a 7mm action with a 308 barrel. The receiver was too hard to stamp. Deal with it Future! You are lucky the gunsmith who worked on that rifle stamped "308". Though I doubt you could have chambered a 7.65 Arg in a 308 chamber.

You could have poured Cerrosafe into the chamber and seen from the slug what chamber you had.

Personally, I would not recommend shooting 308 in a 1891 vintage action. I don't trust the metallurgy from that period. If you ever do any reading about the maturity of steel technology back than, you will discover that it was not very mature. The machine work is great, but the steel manufacturing process technology stunk.

[garryc]

Personally, I would not recommend shooting 308 in a 1891 vintage action. I don't trust the metallurgy from that period.

You are firing a round that has a maximum SAAMI pressure of 62,000 psi in a rifle action ment for about 45,000psi. Even the 7.62x51 nato round is rated at a maximum of 50,000 psi. As a reloader I'd fire it, but with only bottom end loads. What you should do it take it to a gunsmith and have the bolt lugs checked for micro cracks and the action for setting.

[csmsss]

You are firing a round that has a maximum SAAMI pressure of 62,000 psi in a rifle action ment for about 45,000psi. Even the 7.62x51 nato round is rated at a maximum of 50,000 psi. As a reloader I'd fire it, but with only bottom end loads. What you should do it take it to a gunsmith and have the bolt lugs checked for micro cracks and the action for setting.

7.62x51 NATO is loaded to the same, and occasionally hotter pressures as .308. It's just that the pressure is measured using a different process (CIP vs. SAAMI). It is a mistake to think that 7.62x51 NATO is a "milder" version of .308 Winchester.

[Scorch]

7.65X53mm (7.65 Argentine or Belgian) and 308 Win/7.62X51 are loaded to roughly equivalent pressures, and the ballistics are roughly equivalent with similar weight bullets (150 gr bullet @ 2,910 fps vs 150 gr bullet @ 2,750 fps). The Argentine round was among the first small-bore smokeless military rounds developed during the late 1800s, developed at roughly the same time as the 8X57mm, 7X57mm, 7.62X54mm, 30-40 Krag, and a whole truckload of other military rounds. As was common around the world during the late 1950s to early 1960s, the 1891 rifles were rechambered to 7.62X51mm NATO when the Argintine army switched to 7.62X51mm for their standard round, and the rifles stored for use by reserves in case of a war. The rifles were marked over the front ring to positively identify them as rechambered for the newer round. Although it is very probably safe to fire these rifles with 7.62X51mm military ball ammo, I would not feed it a stready diet of these loads, as the action may stretch and develop headspace issues over time.

Personally, I would not recommend shooting 308 in a 1891 vintage action. I don't trust the metallurgy from that period. If you ever do any reading about the maturity of steel technology back than, you will discover that it was not very mature.

And are you a metallurgist? By that logic, Winchester should never have chambered the 1886 for .348 Win (and renamed it the Model 71), the 1885 Winchester should never be chambered for anything other than black powder cartridges, the 1892 Krag should never have been developed from the 1889 Danish Krag, the 1898 Mauser should be suspect, and the the SMLE should be absolutely dangerous. European metallurgy in the late 1800s was stupendous, at least far enough advanced to develop such weapons as the 1893 Mauser, the 1894 Swedish Mauser, the Schmidt-Rubin, the Mannlicher-Carcano, and various other well-respected rifles.

[James K]

Other considerations aside, you can't "rechamber" a 7.65x54 to .308 Winchester; the original chamber is already too big. You can re-barrel, or (within limits) set the original barrel back. Some of those rifles may have been altered by another means, one that IMHO presents potential problems.

The accompanying photo shows a barrel altered by use of a chamber insert; these will work, but I have serious qualms about the effects of high pressure gas working on the gap between the insert and the original barrel.

If the barrel is not new and has not been set back, I suggest your gunsmith check for the presence of an insert.

Jim

[Dcoil03]

Thank you for the advice everyone, I will certainly take the rifle to a gunsmith and have it checked before I ever decide to fire it again.

I especially appreciate your input Scorch. The "Cal 308" stamp is right where you said it would be, on top of the front ring.

Although it is very probably safe to fire these rifles with 7.62X51mm military ball ammo, I would not feed it a stready diet of these loads, as the action may stretch and develop headspace issues over time.

My question now, Scorch, is f I can't shoot 7.62x51 ball, would FMJ .308 be the alternative, or do you suggest another variant?

[Scorch]

My question now, Scorch, is f I can't shoot 7.62x51 ball, would FMJ .308 be the alternative, or do you suggest another variant?

FMJ is ball ammo. If you want to shoot it with military ammo, try the lighter bullet weights. Personally, I would shoot reloads in it. But if you don't reload you can try Wolf 140 gr loads, they seem to be a bit lower pressure from what people on TFL are saying, but I've never fired them

[Hawg]

Personally, I would not recommend shooting 308 in a 1891 vintage action. I don't trust the metallurgy from that period. If you ever do any reading about the maturity of steel technology back than, you will discover that it was not very mature. The machine work is great, but the steel manufacturing process technology stunk.

It's not the metallurgy it's the heat treating or rather the lack of it. Small ring Mausers are chambered for rounds that don't really need it and added more expense and time to the manufacturing process. Factory .308 pressure is about as high as you can go on one of these and firing enough of those rounds through one will eventually lead to receiver stretching but it will take many, many rounds to do so. BTW the 91 Argentine came with a bent bolt. It's not low enough to use with a scope but they were bent. It does sound as if the handle on yours has been replaced.

[Dcoil03]

FMJ is ball ammo. If you want to shoot it with military ammo, try the lighter bullet weights. Personally, I would shoot reloads in it. But if you don't reload you can try Wolf 140 gr loads, they seem to be a bit lower pressure from what people on TFL are saying, but I've never fired them

Oh yeah, I know FMJ = Ball. I was just wondering if you were suggesting factory loads (Remington, Winchester, etc...) instead of the military surplus.

Ironically, the .308 Wolf was the last thing I had fired through it. It cycled just fine. I've fired 7.62x51 NATO Mil. Surplus before and the bolt was difficult to cycle after about 15 rounds. I guess the lower grain factory .308 rounds are way to go, once I get it checked out and everything's given the A-OK.

Thanks for the advice everyone.

[Slamfire]

And are you a metallurgist?

No. Are you? Do you have a technical background? I took materials science, worked in advanced materials research, and for fun, am interested in the history of technology. To include, steel.

By that logic, Winchester should never have chambered the 1886 for .348 Win (and renamed it the Model 71), the 1885 Winchester should never be chambered for anything other than black powder cartridges, the 1892 Krag should never have been developed from the 1889 Danish Krag, the 1898 Mauser should be suspect, and the the SMLE should be absolutely dangerous. European metallurgy in the late 1800s was stupendous, at least far enough advanced to develop such weapons as the 1893 Mauser, the 1894 Swedish Mauser, the Schmidt-Rubin, the Mannlicher-Carcano, and various other well-respected rifles

You have confused metallurgy with design. A M1903 made of proper materials will hold the structural loads it was designed to hold. A M1903 single heat treat, with burnt steel, of inferior composition, won’t. A M71, made of 1930’s materials is plenty strong for the 348. Know anyone who would recommend chambering a black powder era M1886 for the 348?

The materials of those early days are greatly inferior to the same steel made today. Process technology is critical to a quality product. What I have read just leads me to conclude that the steels of that era were highly variable, had slag, all things indicating primitive process controls. This was not evil, they were just at the start of the development of steel technology. They were flame hardening Krag bolts; which explains the cracked Krag bolt I saw, and heard about. Sophisticated steels and standardized steel tests, such as shock tests, were still in development.

Dates in the rapid evolution of metal technology.

Manganese Steel licensed to use in US in 1890

Silicon Steel patented in 1886

Nickel Steel Armor adopted in by US Navy1891,

1910 Monnartz patented Stainless Steel

For those old enough to remember the semiconductor revolution, the big changes that went on from 1980 to 2000, you can recall just how primitive the early 80’s stuff was in comparison to the late 90’s stuff.

Steel technology changed that fast from 1880 to 1920.