Hey guys, I have an Ithaca M-66 SuperSingle 20ga. from my dad. The barrel states that it's a 20ga 3" chamber. Wally World didn't carry 3" 20ga shells, so I got 2-3/4". Is it bad to shoot 2-3/4" shells from a 3" chamber in 20ga? Obviously the reverse would be a very bad idea. Before I call Ithaca, I thought I would ask here. Any one KNOW FOR SURE? Thanks!