Firearms / Pistols / Heckler & Koch Mk 23

Heckler & Koch Mk 23

General Facts

  • TYPE


    Mark 23 MOD 0
    Mk 23 USSOCOM
    OHWS / Offensive Handgun Weapon System (program for which the Mk 23 was developed)

    1989 - 1993

    Heckler & Koch

    1996 - present

    Germany - Heckler & Koch



    Good accuracy and range
    Standard issue silencer
    Powerful and large magazine capacity
    Large and heavy


The Mk 23 is a modern large caliber pistol of German origin. It was developed in the early 1990's by Heckler & Koch as a contender for the Offensive Handgun Weapon System program. This program was to supply US special forces with a pistol powerful and accurate enough to be used as both an offensive and backup weapon. Despite its qualities the size and weight meant that other types of pistols remained in US special forces service alongside the Mk 23. The Mk 23 forms the basis for the highly succesful USP pistol, introduced 2 years later.


The Mk 23 is a large high quality short recoil double action pistol. It has a long barrel with polygonal rifling and muzzle threaded to accept a suppressor. The Mk 23 pioneered the use of a polymer frame, which houses a double stack magazine and accessory rails. The suppressor and laser aiming module were developed specifically for the Mk 23.


The Mk 23 fires the powerful .45 ACP round from 12 round magazines. When introduced this was considered a high capacity magazine in this caliber. The subsonic nature of the .45 ACP makes it ideal for use with a suppressor. Accuracy of the Mk 23 is reported to be very good. Around 4 MOA can be expected at 50 meters, making the Mk 23 more practical for use beyond 25 meters than most other combat pistols.


The Mk 23 was adopted by US SOCOM and was issued to various US special forces units. Various special forces units around the world adopted the Mk 23 in small numbers. Nowadays the Mk 23 remains available, but more practical alternatives are favored. These include newer Heckler & Koch products such as the USP Tactical and HK 45.


Mk 23

The Mk 23 is a large combat pistol that looks very similar to the more commonly used Heckler & Koch USP. The most visible differences from the USP are the longer slide and frame. No true variants of the Mk 23 were made, although markings and frame color changed over the years. Unlike the USP, which is available in various sizes and calibers, the Mk 23 is only available in .45 ACP.

Caliber.45 ACP
OperationShort recoil
Fire selector0-1
Rate of fireSemi-automatic
Barrel length149 mm
Rifling381 mm pylogonal rifling, right hand twist
Muzzle velocity260 m/s
Length245 mm, 421 mm with KAC suppressor
Width39 mm
Height150 mm
Weight1.2 kg empty, 1.47 kg loaded, 2.29 kg loaded with suppressor and LAM
SightsIron sights, adjustable precision sights, 195 mm sight radius
RemarksThreaded barrel


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