Built with ATI's patented .410 Gauge modular upper receiver, the Milsport 410 is the perfect shotgun for small game, large game, home protection and target shooting. Chambered for 2 1/2" .410 Gauge shells, the Milsport 410 is a must have multi-purpose shotgun. Featuring an 18.5" barrel with a custom 13" M-LOK, the Milsport 410 runs on a gas operated, short stroke balanced piston system. Each Milsport 410 comes with one 5 round American Tactical polymer magazine. The Milsport 410 will only operate with the patent pending American Tactical polymer 410 magazine. Every Milsport 410 is built on ATI's Milsport lower receiver and can be converted to 5.56 or 300blk just by changing the upper receiver! Every Milsport 410 upper receiver is built to regular AR spec and can be installed on most mil-spec lower receivers.