M26 modular shotgun. Can be mounted to an M4 or stand alone. This would be great home defense shottie.......
USARMY is getting a bunch of them.
M26 Modular Accessory Shotgun System - Mod Army Guns for Paintball - Popular Mechanics
Defense Tech: Aberdeen Outtakes: M26 Modular Accessory Shotgun System
(video is a little funny, it looks like they were shooting blanks....no recoil???)