HK MK23

Type	Semi-automatic pistol
Place of origin	Germany  United States

In service	1996-present
Used by	See Users

Designed	1990s
Manufacturer	Heckler & Koch
Variants	MK23 Mod 0 (military markets) Mark 23 (civilian and law enforcment markets)

Weight	1.2 kg (2.7 lb), empty 1.47 kg (3.2 lb), loaded 2.29 kg (5.0 lb), loaded, with suppressor and LAM
Length	245 mm (9.7 in), without suppressor 421 mm (16.5 in), with suppressor
Barrel length	150 mm (5.9 in)

Cartridge	.45 ACP
Actio	Short recoil, DA/SA
Rate of fire	Semi-automatic
Muzzle velocity	260 m/s (850 ft/s)
Effective range	25 m
Feed system	Detachable box magazine; capacities: 12 rounds (standard) 10 rounds (restricted)

The Heckler & Koch MK23 is a handgun consisting of a match grade semi-automatic pistol, a laser aiming module (LAM), and suppressor. It was adopted by the United States Special Operations Command (USSOCOM) for special operations units in the 1990s.
While the designation applies to the complete system, it's also commonly used in reference to the pistol component itself. The pistol itself, chambered for the .45 ACP cartridge, was developed by Heckler & Koch, and was selected over the Colt OHWS through USSOCOM's Offensive Handgun Weapon System (OHWS) program. The LAM and suppressor were developed by Insight Technology and Knight's Armament Company (KAC), respectively.
The MK23 Mod 0 was built as an "offensive" handgun for U.S. special operations forces under USSOCOM, as per request made in 1989. Military versions of the firearm have the writing "MK23 USSOCOM" engraved on the slide.
The MK23 is considered a match grade pistol, and is capable of making a 2-inch (51 mm) group at 50 yards (46 m), roughly 4 MOA. Production began in 1991, and it was the basis for the HK USP, which began production in 1993. The MK23 has exceptional durability in harsh environments, being waterproof and corrosion-resistant. It uses a polygonal barrel design, which is reported to improve accuracy and durability. It also features an ambidextrous safety and magazine release on both sides of the frame. The magazine release is at the rear edge of the trigger guard, which is wide enough to allow the use of gloves. A decocking lever is on the left side, which will silently lower the cocked hammer. The MK23 is part of a larger weapon system that includes an attachable laser aiming module, a suppressor, and some other features such as a special high-pressure match cartridge (.45 +P ammunition).
The firearm was tested and found to be capable of firing tens of thousands of rounds without a barrel change. It remains reliable in harsh conditions, making it suitable for use by special forces. The .45 ACP round has considerable stopping power, and yet is subsonic making it suitable for use with a suppressor. Additionally, its shared design characteristics with the Colt M1911 pistol have made it easy for people who have experience with a 1911 to field strip and properly clean the MK23.
However, the firearm's large size and weight have resulted in some criticism. In response, HK developed the USP Tactical pistol based on the original USP; the Tactical retains much of the performance of the MK23 without the bulky size. It uses a different suppressor (due to left handed threading, as opposed to right-handed on the Mk23). An even more compact pistol than the USP Tactical for counter-terrorist and special forces use is the new HK USP Compact Tactical, which also has its own optional LAM. The USP-CT is lighter and is also capable of fitting a suppressor, making it a prime choice for Special Forces on covert operations.
The proposed Joint Combat Pistol (JCP) was intended to accept match grade and +P ammunition. However, it is not clear if the JCP, which absorbed the earlier SOF Combat Program, will be used alongside or replace the MK23 handguns. As of 2006, the JCP has since been renamed and restructured.