Heckler & Koch Mark 23

The Heckler & Koch MK 23, Mk 23 Mod 0, Mark 23, or MARK 23, is a weapon system 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 is 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.

Overview
The MK 23 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 MK 23 is considered a match grade pistol, and is capable of making a 2 in group at 50 yd, roughly 4 MOA. Production began in 1991, and it was the basis for the HK USP, which began production in 1993. The MK 23 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 MK 23 is part of a larger weapon system that includes an attachable Laser Aiming Module (LAM), 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 MK 23.

In spite of its positive points, the firearm's large size and weight have resulted in some criticism. The handgun was designed for offense rather than defense, the size and weight intentionally incorporated to help absorb recoil forces and retain greater accuracy; but this also decreased its ease of use, comfort, and draw speed in defensive situations which require a more conventional, compact pistol. 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. Recently, HK has also developed the HK 45, a much more contoured pistol based on the P2000, P8 and P30 models.

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 MK 23 handguns. As of 2006, the JCP has since been renamed and restructured.

Offensive Handgun Weapon System
The MK 23 was submitted to the USSOCOM Offensive Handgun Weapon System (OHWS) competition around late 1991 the goal of which was to create an entire pistol package capable of replicating the performance of longer barreled weapons such as submachine guns with many customizable features. Its rival was the Colt OHWS. Though both Heckler & Koch's and Colt's designs were tailored to the demanding requirements of the OHWS competition, the MK 23 eventually won.

HK commercially markets the MARK 23 and derivatives of it, but not the complete SOCOM system. The suppressor is made by Knight's Armament Company, and was selected over the one HK originally included as part of its entry. Insight Technology won the contract to produce the laser aiming module, later designated AN/PEQ-6. One version of the LAM produces a visible light dot, while another produces an infrared dot that can only be seen through night vision goggles. There have since been different LAM models and, at least commercially, different suppressors as well. The first MK 23 production models were delivered to SOCOM on May 1, 1996. It has been reported by some users that the cumulative effects of recoil may occasionally cause the can of the suppressor to become slightly unscrewed, but that it is relatively easy to improvise solutions for the problem. Other users say the pistol's large frame size means its wide grips are not always comfortable for people with smaller hands.

Civilian Mark 23
Heckler & Koch is offering the MK 23 on the civilian market and law enforcement as the MARK 23. It is distributed by its subsidiaries HK Inc. (United States) and HKJS GmbH (Germany).

The models for the U.S. market initially came with a 10-round magazine, to comply with the U.S. Assault Weapons Ban. The ban has now expired, and the civilian Mark 23 comes with the same 12-round magazine as the government variants, except in a few states that enforce their own bans on magazines larger than 10 rounds. In Canada, the Mark 23 pistol is still supplied only with 10-round magazines, as per the 1995 Firearms Act.

According to the Operators Manual, there are few differences between the civilian Mark 23 and the government MK 23. These differences are the slide engraving "Mark 23" which is only for the first half of the first year of production in 1996 (KG date code), the roll-mark "MARK 23" which is for mid 1996 to now, these instead of "MK23 USSOCOM", Matte vs shiny finish for different civilian years, tan vs black frame (500 tan ones were made), and a barrel conforming to SAAMI headspace specifications for the military vs civilian made, as the military barrels were made to allow ball ammunition to work more reliably.

Users

 * 🇮🇩 Indonesia: Komando Pasukan Katak (Kopaska) tactical diver group and Komando Pasukan Khusus (Kopassus) special forces group.
 * 🇲🇾 Malaysia: MK 23 MOD 0 adopted by Pasukan Gerakan Khas Counter-terrorism Police Squad of the Royal Malaysia Police.
 * 🇵🇱 Poland: Used by GROM.
 * 🇺🇸 United States: Adopted by the U.S. SOCOM. Deliveries commenced in 1996.

Other sources

 * Jane's Guns Recognition Guide by Ian V. Hogg