The M4 features a modified gas/inertia recoil system designed to function with light tactical loads as well as heavy full dram loads and built to the same tough military specifications with the same reliability that our troops count on. Underneath the M4's purposeful exterior are familiar Benelli features such as a chrome-lined bore and rotating bolt head. Steel parts are black matte phosphate and aluminum matte hard-anodized for low visibility in night operations and corrosion resistance. The dual short-stroke gas pistons are self-cleaning and require zero maintenance. Because of it's design, the Benelli is the fastest cycling semi-auto in the world. Operators who switch from pump shotguns swear that the Benelli doesn't kick at all. The telescoping shoulder stock has 3-positions to accommodate isosceles or weaver shooting stance as well as CQB hold (buttstock held above the shoulder with the weapon slightly depressed below while wearing a heavy tactical vest. The Picatinny rail accepts all red-dot sights.