Rifle of unknown caliber (cartridge)-Mauser, not NEF/H&R

[Johnboy1948]

I bought a rifle advertised as a 7mm on an internet auction. It is a sporterized FN mauser action with an apparent non-military barrel. (The barrel is sightless, smooth, and with excellent dark blueing.)

The barrel is not stamped ANYWHERE as being 7mm or 7x57. I removed the stock and cleaned the entire gun. I calipered the muzzle ID, and it reads about 0.283 inches ID (grooves). A barrel for a 0.284 bullet, it appears.

The auction seller said that he would pay the expense for a gunsmith to determine the caliber (cartridge).

So, how does a gunsmith determine the cartridge? A chamber casting? My Hornady reloading book shows 14 cartridges that use a 0.284 bullet.

Any comments would be appreciated.

Thanks,
John :roll:

[ogo]

My advice,take it to a gunsmith I had a similar experience mine turned out to be 6.5 carsano********ogo

[Leftoverdj]

If it has a standard bolt face and unaltered (straight) feed rails, it's 95%+ likely to be 7x57 Mauser.  You oughta have the headspace checked anyway and a headspace gauge will tell real quick if it's not 7x57.

You could mess around with chamber casts and the like if you wanna.

[Nightrain52]

What LDJ said. Any gun of unknown caliber and condition should be taken to a gunsmith to be checked for headspace and to be sure it is safe to shoot. What a gunsmith charges to do this is well worth it if you want to keep your eyesight, limbs, and assorted fingers. 3 years ago a friend of mine bought a surplus Mauser in 8mm and took it to the range to try it out. Luckily he loaded only one round in it and upon firing it blew out the primer with him getting a face full of hot gases and primer shards. Luckily he was wearing shooting glasses and his eyes were undamaged. He took it to a gunsmith and after a check over the smith told him the bolt wasn't even made for that rifle. The money spent for a smith to check it over is well worth. :eek:  :eek:  :eek:  :eek:  :eek:

[Johnboy1948]

Thanks, guys. Just read all of the replies this a.m. I took the rifle in two days ago on Friday to be checked. The gunsmith's first guess is a 7mm x 65mm, BUT we shall see... He is going to cast the chamber and barrel, make measurements to determine the cartridge. I just hope the chamber and throat are not screwed up to not match anything. Why does gaining experience always cost money?

I was wrong about the barrel. He said that it is military. The barrel evidently was turned smooth on a lathe, and then re-blued. And the gun was probably sporterized in the 1950's based on the stock style and finish. The recoil pad is very hard from age. So the work was done at least 35 years ago. The gun has probably been a safe queen for the last 30 years, as there is very little wear on any of it. And no rust.

Thanks again guys. I'll post again and let you know if it's a shooter or a wallhanger.

John :-)

[Johnboy1948]

The gunsmith says that the rifle is a 7mm (7x57). He test fired it. Brave soul.