Smaller in length and height than the standard HK45, the HK45 Compact (HK45C) features a slim-line grip profile and is otherwise almost identical to the full-size HK45. Like the HK45, the HK45 Compact was developed as a potential candidate for the Joint Combat Pistol (JCP) and Combat Pistol (CP) programs run by the U.S. military in their search for a new service handgun. These programs were halted before they were completed, and no pistols were chosen. The HK45 Compact uses an HK proprietary O-ring barrel for precise barrel-to-slide lockup and optimal accuracy.