Yes, although some semi-auto shotguns chambered for a 3" won't function properly with a 2 3/4 because the energy may be too low to cycle the gun properly. I can't think of any pumps that won't feed ok with 2 3/4 and obviously all single shot or double barrels will work fine. The shotgun shell is positioned in the chamber by the "Rim" of the cartridge, just like regular 22, 45 LC or 38/357 cartridges, so as long as the maximum length or shorter cartridge is used everything will work fine.
The "rimless" cartridges used in most semi-auto or full auto firearms like the 9mm, 45 acp, 40, 38 super, 308 rifle etc. are held in position in the chamber by the "top edge" of the brass, normally these are limited to one cartridge (brass) length for that reason.