Chamber length looks to be about 2.63. A 3" shell will drop right in ( not that I would shoot one, just checking chamber depth) Both bores are mirror like, but the right barrel seems to have some lines running parallel with the bore for about 6" past the chamber. Don't clean out with bore cleaner, almost looks like plastic smears from wads. Have some older Federal low base game loads, 2 3/4 dram 1oz that I might have to try