Heckler & Koch Mark 23

For the Mark 23 Mod 0 machine gun, see Stoner 63.

Heckler & Koch MK 23
MARK 23 equipped with suppressor and laser aiming module.
Type	Semi-automatic pistol
Place of origin	Germany
Service history
In service	1996-present
Used by	See Users
Production history
Designed	1990s
Manufacturer	Heckler & Koch
Produced	1996 - present
Variants	MK 23 Mod 0 (military markets) Mark 23/MARK 23 (civilian and law enforcement markets)
Specifications
Mass	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
Action	Short recoil, DA/SA
Rate of fire	Semi-automatic
Muzzle velocity	260 m/s (850 ft/s)
Effective firing range	25 m
Feed system	Detachable box magazine; capacities: 12 rounds (standard) 10 rounds (restricted)

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-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 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.

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.

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

In 1989, US SOCOM began reviewing their equipment to see which gear fit the needs of their special close quarters battle role. Studying small arms revealed that there were 120 types and configurations of infantry weapons in different units. The logistics of getting spare parts for all these weapons was overwhelming. In response, SOCOM decided to standardize small arms among all units. One area of improvement was the pistol, undertaken by the Offensive Handgun Weapon System competition. It would replace pistols like the 9 mm M9, which was used by regular troops as a secondary weapon. SOCOM's use of small units that operate in close means that pistols are more likely to be used as primary weapons.

The caliber for the OHWS was quickly decided not to be the NATO standard 124 gr (8.0 g) 9 mm due to lack of stopping power. The FBI had selected the 10 mm auto to replace their 9 mm pistols, but it was too powerful, few manufacturers produced it, and the round caused short weapon service life. The .45 ACP caliber was chosen and improved upon with the high velocity, high pressure 185 gr (12.0 g) +P loading.

The OHWS pistol had to fire many types of rounds in addition to the +P cartridge and have a long service life with the high pressure ammo. The M1911 had been proven in service for over 70 years, but was rejected. High pressure rounds would destroy it and it did not fire reliably with a suppressor. Upgrading the M1911 would cost more than it was worth, so it was decided that they would select an entirely new design. A request for quote was for a system that included a pistol, suppressor, and laser aiming module. The pistol had to be corrosion resistant, have a high mean rounds between failures (MRBF), and be able to serve as a primary weapon.

After several tests, Heckler & Koch and Colt submissions were selected to move to phase I of the OHWS program in August 1991. They were awarded developmental contracts to produce 30 systems. At the time the program was beginning, HK was studying what aspects were most desirable in handguns for the U.S. civilian market. They came up with a design that had these features including reliability, durability, affordability, and others by February 1991. Colt however essentially drew upon existing technologies for their submission called the Colt OHWS. They used an M1911 frame that could accept a 10-round magazine, the decocking mechanism from the Colt Double Eagle, and the rotating barrel locking system from the All American 2000. The barrel of the Colt OHWS could not directly attach a suppressor, so a mounting was added to a rail in front of the handguard.

Colt was eliminated after phase I, leaving only HK to move on to phase II. This phase subjected the pistols to the strictest reliability testing any pistol ever went through. The requirement was for no less than 2,000 MRBF; the HK OHWS averaged 6,027 MRBF and could reach 15,122 MRBF. Three pistols went through a 30,000-round endurance test and maintained accuracy of 2.5 in (64 mm) at 25 meters; only the O-ring needed replacement after 20,000 rounds. The weapons worked in temperatures from -25 degrees fahrenheit to 140 degrees fahrenheit while exposed to mud, ice, and sand. Phase III was the awarding of a production contract to HK in June 1995. Their pistol was type classified as the Mark 23 Mod 0, and 1,950 systems were ordered at $1,186 each. All pistols were produced in Germany and the first was delivered to SOCOM on 1 May 1996.

Even though the Mark 23 had performed admirably, several factors worked against its use. Previous operators were trained to fire multiple 9 mm rounds and they thought firing extra rounds made up for not using harder hitting but larger and heavier .45 ACP rounds. The introduction of the smaller and lighter HK USP, political pressures, and shortages of +P ammunition also contributed against the pistol. As the War on Terror went on, operators saw the effectiveness of the .45 ACP in combat and renewed use of the Mark 23, as well as other pistols chambered for the round.

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.

See also

• Heckler & Koch USP, pistol based on the MK 23.
• Heckler & Koch, the manufacturer.
• List of individual weapons of the U.S. Armed Forces

Other sources

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

External links

• Heckler & Koch Mark 23 at the Internet Movie Firearms Database
• Mark 23 Official website
• HKpro SOCOM page
• MK 23 Video