The LWRCI M6 Individual Carbine family is a direct descendant of the rifles developed to meet the requirements of the US Army individual carbine program while maintaining the basic M4/AR15/M16 architecture. The short stroke gas piston operation provides you with the ultimate in reliability in a variety of harsh real world conditions. The Monoforge upper receiver features a modular rail system that is machined as part of the upper receiver for added strength and reduced weight.