Lower receiver is fitted with Magpul® MOE® grip and MOE SL® collapsible buttstock on a Mil-Spec buffer tube.Handguard is free-floated for accuracy and the slim, 15″ length provides enhanced ergonomics.To support the large case head of .450 Bushmaster ammunition, the .450 Bushmaster bolt is engineered with tapered lugs and machined from a high-strength superalloy.The Ruger® Elite 452® AR-Trigger is a two-stage trigger that offers a smooth, crisp, 4.5 pound trigger pull. It features a full-strength hammer spring for consistent primer ignition and a lightweight hammer that enables a faster lock time for improved accuracy.Magpul® M-LOK® accessory attachment slots along the 3:00, 6:00 and 9:00 positions with additional slots on the angled faces near the muzzle.Ruger® muzzle brake is a radial port design that significantly reduces felt recoil and muzzle movement. The threaded barrel allows for standard muzzle accessories to be installed.Cold hammer-forged 4140 chrome-moly steel barrel with ultra-precise 5R rifling and black nitrided finish provides exceptional accuracy, longevity and easy cleaning. The heavy barrel profile and 1:16″ twist rate maximizes accuracy with bullets ranging from 170 to 260 grains.Made from aerospace-grade 7075-T6 aluminum forging, the flat top upper receiver includes a forward assist, dust cover and brass deflector, and is Type III hard coat anodized for maximum durability.Bolt carrier and gas key have chrome-plated inside diameters to provide exceptional resistance to hot gases. The gas key is staked so that it will not loosen after extensive firing.Carbine-length gas system provides the most reliable function with .450 Bushmaster ammunition.Also includes: one, 5-round metal magazine.