The Heckler & Koch MK 23, MK 23 MOD 0, Mark 23, or USSOCOM MARK 23 is a semi-automatic large-frame pistol chambered in .45 ACP, designed specifically to be an offensive pistol. The USSOCOM version of the MK23 came paired with a laser aiming module (LAM) and suppressor. The USSOCOM MK23 was adopted by the United States Special Operations Command (USSOCOM) for special operations units, beating out the nearest competitor, Colt's OHWS. Development of the pistol began in 1991 as special operations representatives identified the need for an "Offensive Handgun Weapons System—Special Operations Peculiar", and delivery of the pistols began in May 1996 to the special operation units.
While the USSOCOM MK23 designation usually applies to the complete system, it is also commonly used in reference to the pistol component alone. The LAM and suppressor were developed by Insight Technology and Knight's Armament Company (KAC), respectively. The civilian version of the Mk23 sold by itself is designated the Mark 23.
Overview
The MK 23 is considered a match grade pistol, and is capable of making a group at . The MK 23 is designed for exceptional durability in harsh environments, being waterproof and corrosion-resistant. It uses a polygonal barrel design, which is reported to improve accuracy and durability, and is much more expensive to produce. 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 is subsonic in the standard loading, making it suitable for use with a suppressor.
Development
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 (OHWS) 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 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 +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.
