How to figure out what a rifle is chambered in?

[302w 83]

I inherited a 1909 Peruvian Mauser that is nicely sporterized. The only original pieces are the receiver, magazine, and possibly bolt. If the bolt is original it has a new handle. I think any collector value is long gone.

 

It was rebarreled and reblued at some point in its life. I do not know who made the barrel. The firearm itself was originally 7.65x53 Argentine, and now a poorly made dummy .308 round will fit in the magazine, chamber, and will eject. I have not tried live ammo.

 

Is there a proper way to determine what it is chambered in? Or if it will fire 7.62x51 and .308? I have not disassembled it yet.

[ccrides350 1]

I'm pretty sure a chamber cast needs to be taken.

[T Bill 649]

They were chambered in 7.65 x 53 I believe.  A cast would definitely need to be done to be sure.  Action is reused for custom builds.

[njJoniGuy 2,131]

Not only a chamber cast, but you would be well served to slug the barrel.

That's the last place you want to be surprised with a live round in the rifle.

[GRIZ 3,369]

It will probably shoot a 7.62x51 if it's chambered in 7.65x53. The extractor will probably hold the case head for the firing pin to hit the primer. The 7.62 bullet rattling down the 7.65 bore will result in poor, if any, accuracy. The cases will also look very different if they stay in one piece.

 

As noted, a chamber cast and bore slug are called for. You can get what you need to do it from Midway or Brownells.

[Smokin .50 1,907]

What everyone else said about chamber checking and slugging.

 

If you decide to shoot 7.62 NATO or .308 out of it, in addition to what was already mentioned, after they finish "rattling" down the bore, they may spin wildly and key-hole sideways into yer target.  If they do, THAT will be a BIG CLUE as to what's up....

 

Anybody else here on the forum have some 7.65 x 53 to loan the OP to see if it chambers?

[302w 83]

I found an easier way to figure out the caliber.

 

Disassemble the rifle.

 

It appears to be hand stamped with:

CW

2/65

308

 

Woo hoo! Precision rifle time!