Model 97's in 12ga are all 2 3/4" chamber length.
They were cut that way from the start of production.
If you measure the chamber length (of a TD model) by simply using the disassembled bbl assembly, you WILL come up with the short chamber length of 2 1/2+" chamber length.
That is because the other 1/4" of the actual chamber is inside the action in the form of the 'chamber ring' that that the bolt fits up against on the inside,,and the bbl fits against when in place on the muzzle side.
That ring and it's 1/4" length is part of the chamber and it's length.
Lengthening the chamber based only on the bbl and that 2 1/2" measurement will leave you with a 3" chambered gun when all is done. The bbl will be (recut to) 2 3/4",, and then add the 1/4" chamber ring.
Winchester did not start marking chamber lengths on the guns till 1935. That's when the 3" 12ga shell was intro'd. Though the M97 was never offered in 3" 12ga, the M12 was.
What some do to 'improve' the older guns is to lengthen the forcing cone. The older forcing cones are short and abrupt. That was for a good seal w/the card & fibre wads of the day.
Recutting the F/Cone to a more gentler angle is more appropriate for the plastic wads used now and can reduce recoil a bit.
However there is only so much metal in the bbl and some careful measureing of the bbl wall must be done before doing and chamber length/forcing cone work. Eyeballing it does not count.
Most of the time all these 'improvements' are un-needed and the guns are just fine as they are.
Great looking 97's
They were cut that way from the start of production.
If you measure the chamber length (of a TD model) by simply using the disassembled bbl assembly, you WILL come up with the short chamber length of 2 1/2+" chamber length.
That is because the other 1/4" of the actual chamber is inside the action in the form of the 'chamber ring' that that the bolt fits up against on the inside,,and the bbl fits against when in place on the muzzle side.
That ring and it's 1/4" length is part of the chamber and it's length.
Lengthening the chamber based only on the bbl and that 2 1/2" measurement will leave you with a 3" chambered gun when all is done. The bbl will be (recut to) 2 3/4",, and then add the 1/4" chamber ring.
Winchester did not start marking chamber lengths on the guns till 1935. That's when the 3" 12ga shell was intro'd. Though the M97 was never offered in 3" 12ga, the M12 was.
What some do to 'improve' the older guns is to lengthen the forcing cone. The older forcing cones are short and abrupt. That was for a good seal w/the card & fibre wads of the day.
Recutting the F/Cone to a more gentler angle is more appropriate for the plastic wads used now and can reduce recoil a bit.
However there is only so much metal in the bbl and some careful measureing of the bbl wall must be done before doing and chamber length/forcing cone work. Eyeballing it does not count.
Most of the time all these 'improvements' are un-needed and the guns are just fine as they are.
Great looking 97's