Does the standard barrel for a Remington 1100 Magnum shotgun have a two and three quarters inch or three inch chamber?

i am pretty sure they are 3" You can shoot 2 and 3/4 in.shells in the 1100 3"mag but, the shot weight has to be at least an ounce and 1/4 for it to cycle {fire,eject and chamber the next shell} properly.