How do you know what the gun is chambered for?

[Bleeh]

I've got an old s/s .410, How do I know what it's chambered for? I can fit a 2.5 inch cartridge down the barrel, does that mean it's safe to use?

[Trussman]

It should be printed on the barrels, or the proof marks should reveal the answer.

[clayman]

The chamber length is the length of the FIRED cartridge - hence you can put a 3" magnum into the breach of a 2 1/2" chamber and close the gun successfully - but if you fire that cartridge the crimp will not be able to open fully, the pressure will be excessive, and chances are you will blow the side out of the gun.

 

Just becuase a cartridge will fit in a gun, does not mean its safe to use. NEVER use a cartridge that the case OPEN is longer than the chamber. The closed or unfired shell case will be about 3/8" shorter than the chamber its designed for, to allow room for the crimp to open fully.

 

The chamber length is marked as part of the proof markings

[clayman]

Hi Clayman,

 

Is that a "yes" to me being able to use my longer 70mm carts?

 

Cheers

Darryl

 

Yes.

 

From the markings you describe, the gun is proofed for 70mm max carts - so as long as the manufacturer of the cartridge declares them as 70mm ( 2/3/4"), or less, the cartridge is safe to use.

 

Do not, just measure an unfired cartridge length, this is always less than the declared fired length - always use the manufacturers size as written on the shell box.