The HK USC is a civilian utility carbine that uses the classic hard-hitting .45 ACP cartridge. Matched with a simple and ultra-reliable blowback operating system, the HK USC is a radical departure from traditional firearms designs. Extensive use of durable, tough, corrosion proof, reinforced polymers found on HK's line of military and police arms ensures lightweight and durability and the highest grade of weapons steel is used in the cold hammer forged target barrel and the solidly constructed bolt mechanism. The skeletonized buttstock is capped with a comfortable rubber cheek rest and recoil pad. The web of the pistol grip is open for a comfortable handhold for a wide range of shooting applications. Hard points located on the top and sides of the receiver and handguard make attachment of optional Picatinny rails easy allowing almost any kind of accessory to be mounted. Guns.com Full Review of the HK USC in .45 ACP.