A Super X3 with a 3 1/2" chamber is designed to shoot factory 12 gauge loads including   2 3/4", 3" and 3 1/2" (1 1/8 oz. to 2 1/4 oz.) field loads.  They are not designed to shoot the lightest factory 7/8 oz. or 1 oz. target loads.

Can I shoot 2 3/4" shells in my 3" Super X3 shotgun?

A field Super X3 with a 3" chamber is designed to shoot factory 12 gauge loads including 2 3/4" and 3" (1 oz. to 2 oz.) field loads.  They are not designed to shoot the lightest factory 7/8 oz. or 1 oz. target loads nor any 3 1/2" shells.

A Sporting Super X3 will shoot the lightest 7/8 oz. target loads to heavy magnum loads (2 3/4" only).