The Heckler & Koch Mk 23 Mod 0 became a specially-formulated, semi-automatic pistol developed for United States Special Forces under the direction of United States Special Operations COMmand ("SOCOM") (corresponding Mk 23s are labeled as such along their slide assembly). The weapon's complete name became "Offensive Handgun Weapon System" and paired the reliable action of the Heckler & Koch USP (Universal Self-loading Pistol -though slightly modified with a longer slide and barrel) with the powerful .45 ACP cartridge. Additionally a Laser-Aiming Module (LAM) was fitted ahead of the trigger guard and a sound suppressor added for clandestine work. Introduced during the mid-1990s, the SOCOM pistol is still in use today (2016).
Overall, the basic gun section portion of the Mk 23 takes on a conventional form as semi-automatic pistols go. The finish is flat black so as not to reflect light sources and construction if a mix of metal and polymers. The trigger loop is large enough for use with a gloved hand. The weapon was first requested by SOCOM in 1990 to replace the venerable Colt M1911A1 .45 ACP series and two designs were returned - one by Heckler & Koch of Germany utilizing a modified version of the USP pistol and the other from Colt with a Knight's Armament suppressor fitted.
From this pair came thirty Phase 1 examples (30 delivered from each company for evaluation) to which the Heckler & Koch design won out over the Colt submission in 1991. Interestingly - the Knight's Armament suppressor as fitted to the Colt design was selected ahead of the HK-sponsored suppressor. The LAM selected for the SOCOM pistol became an Insight Technology product.
Testing of the gun continued throughout 1992 and into 1993 to which the formal procurement contract was announced in 1994 for some 1,380 pistols. The "Mk 23 Mod 0" was officially introduced in 1996 with deliveries forthcoming in May of that year. The Mk 23 enjoys continued service today with United States forces (including the Navy SEALs)as well as Indonesian, Malaysian and Polish special forces groups and special police units.
The subsonic nature of the .45 ACP cartridge in the Mk 23, coupled with the added suppressor, reduces the telltale audible sounds of the firing action and the integrated LAM allows for quick-reaction accuracy in low-light levels. The LAM can project a visible, or infrared dot, and the optional assembly is backed by traditional tritium iron sights. Overall weight of the weapon system is roughly five pounds when fully loaded and accessorized while overall length is 16.5 inches when the suppressor is fitted. The action of the pistol is semi-automatic with a short-recoil operating system and Double-Action (DA) trigger pull. The large .45 ACP cartridge is a proven man-stopper and traces its roots to the fine lineage established by the excellent American Colt M1911 pistol of 1911. The pistol grip is coated for a firm hold and there are ambidextrous safety and magazine release controls. The 6-inch barrel resides under the moving slide in the usual way while protruding slightly ahead of the slide at the muzzle end in order to accept the suppressor. Operation of the weapon is as in any other semi-automatic weapon in which the slide is forced back with each successive shot, prompting a fresh cartridge to be pulled from the spring-loaded magazine fitted into the base of the pistol grip. The standard magazine count is 12 x .45 ACP cartridges though - in the modified civilian market "Mark 23" variant - there stands a 10-round magazine to conform to the US Assault Weapons Ban (which has since expired).
The Mk 23 system design takes special care in its firing mechanism to hide the recoiling slide by use of an additional recoil buffer making the SOCOM pistol a particularly lethal special operations weapon where surprise and reliability are key. The lower recoil action then theoretically promotes improved accuracy. A slide lock is also built into the pistol which allows the gun to be fired in the normal manner when the suppressor is in place in order to further keep the element of surprise in check.
As a special forces sidearm, the Mk 23 is built to the highest standard and exacting specifications ensuring reliability and robustness in-the-field for missions that do not conform to "accepted" battlefield standards. The Mk 23 is, therefore, put through rigorous testing and has since become a proven system of lethality. Beyond its use by US SOCOM, the Mk 23 is a sidearm of choice for GROM Polish Special Forces, Indonesian special dive groups and commandos and Malaysian police groups.
The uniqueness of the Mk 23 series pistol is such that it is popularly allows it to be simply referred to as the "SOCOM Pistol".