The Sierra .22 Long Rifle AR-15 Upper quickly attaches to your centerfire AR-15 lower for practice using the same size, weight and trigger with lower-cost rimfire ammo. The forged, flat top M4 upper has been test fired for reliable functioning. Its chrome-moly vanadium steel barrel has 1:16 barrel twist for consistent shot placement. The barrel is Weapon Armament Surface Protection (W.A.S.P.) treated for improved wear, abrasion and corrosion resistance. Anti-jam charging handle. Magazines sold separately. Made in USA.