I am trying to determine the chamber length of my Remington 1900 shotgun (steel barrels, not damascus) because I am working up some blackpowder paper loads.
Alot of people have suggested that older shotguns chambered in 12 gauge have chamber lengths all over the place, 2-1/2", 2-5/8" and 2-3/4" being the most common. From my understanding, chamber length is measured by the length of a FIRED shell? So theoretically, if my gun chambers a 2-3/4" round, that doesnt mean it is necessarily safe for a 2-3/4" shell. So I placed a 3" shell in the gun, and it chambered fine. Does that mean, I am probably safe to use a 2-3/4" shotshell, as the UNFIRED length on a 3" shell is approximatly 2-3/4"?
I tried to run the butt end of a dial caliper end to what I could observe was the 'chamber end' and though not exactly precise, was definatly over 2-5/8" and I believe like 2.70". Am I safe for 2-3/4" shells??