I recently purchased a Winchester 1897, serial number 428***. So it was made in 1909. I'm fairly certain its a riot version. It has a 20 in barrel with a full choke. There are no markings for the chamber size. From what I have read, it should be 2 5/8 or 2 9/16. But either way I have visited every gun shop and chain store like gander mtn. and farm and fleet and have mostly come across 2 3/4 or larger. One gun shop had 2 1/2. Would it be ok to shoot the 2 1/2 shells? Or even 2 3/4 light loads?