Lot of 3 Heckler & Koch OEM HK45C USP Compact. 45ACP 10-Round Magazine w/ EXT – 50248620. The Heckler and Koch HK45-C / USP-C Magazine for. 45 ACP is a high-quality accessory designed to complement the HK45-C (Compact) and USP-C (Universal Self-loading Pistol Compact) models. It boasts a 10-round capacity, making it an excellent choice for personal defense, law enforcement, or recreational shooting. Model- HK45C / USPC.