Heckler & Koch Threaded Barrel HK45 Tactical 45 ACP Black. This is a drop-in barrel for any of the HK45 full-size pistols. No gunsmith is required as this is an easy and quick install. Thread 16x1 left hand Polygonal rifling cold hammer forged 5.11" length barrel. Specifications for Heckler & Koch Threaded Barrel HK45 Tactical 45 ACP: Manufacturer: Heckler & Koch Color: Black Caliber: .45 ACP Gun Make: Heckler & Koch Gun Model: Heckler & Koch HK45 Condition: New Last Chance: Yes Package Contents: Heckler & Koch Threaded Barrel HK45 Tactical 45 ACP What firearm models does the manufacturer say Heckler & Koch Threaded Barrel HK45 Tactical 45 ACP is compatible with? The manufacturer suggests that Heckler & Koch Threaded Barrel HK45 Tactical 45 ACP is compatible with Heckler & Koch HK45Heckler & Koch 51000983: Threaded Barrel for HK45 45 ACP Black