CO2 powered BB guns are great fun for plinking and target shooting. Check out this HK USP. It holds 22 rounds in a heavyweight magazine that also houses the CO2 cylinder that powers this BB pistol. It has an ambidextrous magazine release, integrated accessory rail and realistic hammer movement. This is a great practice pistol for 9mm USP owners. For just pennies a shot you can shoot for hours. This is the non-blowback or standard action version of the HK USP.