If any shotgun you're looking into is chambered for 3", then it will load & shoot both 3" & 2-3/4" cartridges. Also, in some cases may cycle the mini slug 1-3/4" shells.

Hi Robert and welcome to the forum. No Sir, shotguns with 3" chambers will fire 3 inch, 2 3/4-inch or shorter shells no issue. Same concept as a .357 Magnum being able to fire the shorter .38 Special rounds. Single action Shotguns like Pumps, Lever, Double Barrel and Single Shot Break Action can fire mini shells as well, except for most Semi-Auto. Shotguns due to lack of generated cycling power of mini shells Cheers and stay safe!