1915 was the second year production for 12 gauge and 16 gauge Model 12's. . The 12 gauge began life with 2 3/4" chambers, so no need to measure chamber length. . If your gun is early 1915 it may have the early receiver top where the sighting plane wavy lines are only etched into the top only and not set into a groove, on the receiver top, as all other models after that had.
The early 20 ga M12's had 2 1/2" chamber and the early 16 ga. had 2 9/16: chambers.
To help determine value on early plain barrel Model 12, 12 gauge, aside from general appearance and original condition.
- original buttplate will add value, subtract for after market pad
- excessive bolt droop. . If the gun was run dry and dirty over the years it may have developed excessive bolt droop. . To check this; press your middle finger up the shell carrier until you're pressing up on the rear of the bolt. . If the bolt moves up and down more than 1/32" to max 1/16", there's excessive bolt droop and this subtracts from the value even as a shooter grade.
- position of the takedown adjustment bushing. . take the gun down and hold the muzzle down and look at the threaded take down bushing. . Looking down, the adjustment grooves should be mostly all to the left of the bushing locking lug. Preferably still on the first or second notch. If all the grooves are mostly to the right, then all the adjustment is used up and the gun will need the next size bushing which are difficult to obtain today and does detract from the value as a shooter. .
If the gun is in decent original looking condition with a shiny bore and the above mentioned factors are all good; your gun should be worth between $400 to $525. . If the gun gun is well worn, after market pad with droopy bolt and used up takedown bushing it's worth $200 to $250.. An early Model 12, in decent original condition, would make someone a nice upland or pheasant gun as these early nickel steel guns were very nice handling guns and many prefer them to the later models which some claim to be a heavier gun. . The only negative I've found with the early nickel steel guns , is the perch belly stocks were a tad short but the quick handling of these stocks make up for it.