How to measure chamber length

lawsonz

I am trying to determine the chamber lenght on my model 12 16ga. I had a gunsmith look at it with some gauges. I have a fired 2 3/4 shell the i have filled the inside the make solid that will chamber in the gun. The gunsmith initially said the gun was 2 3/4 chambered. Then he took the barrel off and measure it with a guage and said it was not. Wouldn't taking the barrel off eliminate that little bit of length that the receiver adds to the chamber? What would be the proper way to measure chamber lenght of a pump?

rcoane

Lawsonz, I took my model 12 12ga apart and there is a 1/4 spacer in the reciever. On the barrel it meassures 2.5" to the beginning of the taper in the barrel. Barrel clearance + space = 2 3/4. Hope this helps.

tsr1965

Take a machinist pocket 6 inch scale or a set of vernier calipers, and measure the depth of the chamber from the lip in the throat to the breech where the rim of the cartridge seats. Then subtract half of the diameter of the shell(the half diameter is the amount needed for the crimp to open up). This will be your resulting chamber length.

Best

JOHN42768

Hi, According to Dave Riffle 's book "The Greatest Hammerless Repeating Shotgun Ever Built: The Model 12", Winchester changed from 2 9/16 to 2 3/4" chamber in 1926. The 1926 serial range was 423057--464564. If yours falls in the later part or after that range it would be 2 3/4" .Happy New Year. John