My grandfather passed on 3 of his 15 rifles to me. A 1952 Remington 760, A savage 99, and this Model 12. The note says he got it when he was 16 years old and looking up the serial number 121xxx it dates to 1916 which would be correct. Its a 20 guage in good shape. I have cleaned it all up and after using the other 2 rifles above I was ready to put this to use - here lies the problem or where i need more information. It is 2 3/4. I'm not a shotgun expert but thought i read somewhere the older shotguns were 2.5........the serial numbers on the barrel and receiver match. photos attached......I do know that his father had a hardware store in Montana from 1895-1930's..and he sold savages and winchesters and knew all the reps - doubt that has any meaning but just trying to learn about this family shotgun. Thanks...