Is this a 243 or 270?

[runningathewall]

I inherited a gun from my father. I know he built a 270 and I'm pretty sure that's what this is. I also know he had a 243, but I don't know if he made his 243. Although I'm fairly certain it's a 270, the small doubt I have makes me not want to try and shoot it. These are the only makings I found on it.

 

[NIGHTLORD40K]

So, you appear to have a Czech large-ring Mauser action there, made by CZ, but beyond that those markings are useless.

The original chambering would most likely have been 7.92 (aka 8mm) Mauser, but it could be anything now. If it has been rechambered or rebarrelled, the marking SHOULD be somewhere on the barrel. Try removing the stock and looking at the underside of the barrel.

There is a significant difference between .270 and .243 cases, with the .270 being much longer for one thing. It should not be possible to accidentally chamber a .270 cartridge in a .243 barrel, but may be possible to chamber a .243 in a .270.

You cannot rule out that it may be some other chambering entirely either.....

If you cannot locate a marking on the underside of the barrel, a qualified gunsmith should take a chamber casting to be sure.

Good luck!

 

[1MoreFord]

Just as you should not be able to get a .270 to chamber in a .243 you should not be able to get a .270 bullet to go anywhere near into a .243 barrel muzzle. It should be obvious. Get some calipers and measure the muzzle ID or try to stick a .270 bullet into the muzzle. Do all to be certain.

 

[stringnut]

I second getting a chamber cast done. You have no idea what it is for sure. Slugging the barrel would get you the caliber. However you still would have no ldea what the chamber is like. It could still be any number of wildcats that could get you into trouble if a factory cartridge is fired in them.

 

[ms6852]

You can also slug the barrel using an egg shape sinker. If the sinker measures 6.2 mm in diameter it is a .243, if it measures 7.0 mm it is a .270.

 

[jmr40]

Any cartridge markings will be on the barrel, not the receiver. Check that more closely. On custom rigs it can be marked on the top, where it can be hard to see with a scope mounted, or on the bottom of the barrel where it can't be seen until removed from the stock.

 

[runningathewall]

Awesome!! Thank you all so much! I am pleasantly surprised about the information you guys gave me. I also inherited a couple other guns form different family members, such as my grandfather and uncle, but at least those have markings on them. I tried to look all over, but I didn't take the stock off. I will do that to see first.