HK MK 23

The HK MK 23 and the HK Mark 23 .45 ACP pistols give shooters match grade accuracy equal to that of the finest custom made handguns - yet they exceed the most stringent operational requirements ever demanded of a combat handgun. The MK 23/Mark 23 provides this accuracy without the need for hand-fitted parts common in custom-built match pistols costing thousands of dollars more. Repair of the MK 23/Mark 23 is reduced to a simple parts exchange.

The HK Mark 23 is a commercial model of the U.S. Government issue MK 23, MOD 0 Offensive Handgun and is available in limited numbers. Designated the "Mark 23", it is almost identical to the MK23, MOD 0 pistol used by the Special Operations Command, right down to its threaded barrel. The principal differences are slide inscriptions (Mark 23 as opposed to MK 23) and a barrel manufactured to SAAMI headspace specifications. Commercial Mark 23 pistols come supplied with 10-round magazines. Military and law enforcement models have 12-round magazines like the Special Operations model.

One of the most thoroughly tested handguns in history, the MK23/Mark 23 project originated in 1991 when HK was awarded a development contract for the Special Operations Forces Offensive Handgun Weapon System, consisting of a caliber .45 pistol, detachable sound and flash suppressor, and laser aiming module (LAM). The barrel is threaded to accept accessories such as a flash and sound suppressor and the unique HK polygonal bore profile increases muzzle velocity and service life, reduces bore fouling, and eases cleaning. Molded into the frame are special accessory grooves for attaching a light or laser aimer. However, the suppressor and LAM are not being developed by HK and cannot be obtained from Heckler & Koch.

During testing, MK 23 pistols met the most stringent operational and accuracy requirements ever demanded of a combat handgun. MK 23 pistols achieved match grade accuracy with an average of 1.4 inches extreme spread in 5-round shot groups at 25 meters with service ammunition. Endurance testing demonstrated a service life of over 30,000 rounds of +P ammunition, with an additional 30,000 rounds certified on the slide and frame.

To meet the reliability requirement, the pistol had to demonstrate a minimum of 2,000 mean rounds between stoppages (MRBS) with both M1911 ball and +P ammunition. All pistols exceeded the 2000 MRBS with an average of 6000 MRBS.

In more than 450 accuracy test firings from a precision firing fixture, MK 23 pistols far exceeded the government requirement, averaging 1.44 inches, with 65 groups of less than one inch. There were four groups of .5 inches, with 5 rounds going through the same hole! This included firing with and without the sound/flash suppressor attached. Three pistols were tested for accuracy after firing over 30,000 rounds, the specified service life of the pistol, and still met the new pistol accuracy requirement. An innovative design feature, a high temperature rubber 0-ring on the barrel that seals the barrel in the slide until unlocking, led to this remarkable achievement. The 0-ring lasts bevond 20,000 rounds and can be replaced by the operator without tools in seconds.

To meet operational environmental requirements, the pistol was function tested at +140 and -25° F, exposed to 2 hours of submersion in sea water at 66 feet, placed in surf, salt-fog, sand-dust, mud, icing, unlubricated, and fouled environments. A special maritime surface coating protected the pistol from any corrosion, in all of these operational environments.

The frame mounted MK 23 decocking lever is separate from the ambidextrous safety lever. It allows the hammer to be lowered quietly and safely from the single action position. When the hammer is down, the ambidextrous frame mounted safety lever is locked in the fire position so that the pistol is always ready for double action operation. When the hammer is "cocked and locked" in single action mode with the safety lever on "safe", the decocker is blocked so that the pistol is always ready for single action operation. Even with the safety lever engaged, the slide can still be manipulated to load and clear the pistol. The extended slide release lever and the ambidextrous magazine release are easily actuated without adjustment of the firing grip using the firing hand thumb or index finger.

Other notable features include a mechanical recoil reduction system that reduces recoil forces to the shooter and components of the pistol by as much as 30%, a reinforced polymer frame, a one-piece machined steel slide, and a law enforcement/military capacity of thirteen rounds (twelve rounds in the magazine, one in the chamber).

The weapon is aimed using either iron sights or an optional laser aiming component (currently under development). The iron sights provide a 3-dot sight picture with white or optional self-luminous tritium dots.

The Heckler & Koch Special Operations Handgun is designed to fire a minimum of 30,000 rounds of +P ammunition prior to depot level maintenance. After depot level maintenance, the pistol must have at least 30,000 rounds ofadditional service life on the slide and frame.

The MK 23 became the first caliber .45 ACP pistol to enter U.S. military service since the venerable Government Model 1911A1. On May 1, 1996, the first MK 23 pistols were delivered to the U.S. Special Operations Command for operational deployment.

MK 23 Technical Specifications
Caliber .45 ACP
Ammunition Feed Staggered magazines;
10- or 12-round capacity
Rifling Polygonal bore, right hand twist
Sight Radius 7.76 inches (197mm)
Weight: with empty magazine 2.66 pounds (1.21 kg)
Weight: with loaded
12-rd magazine
3.47 pounds (1.576 kg)
Barrel length 5.87 inches (149mm)
Overall length 9.65 inches (245mm)
Width 1.53 inches (38.8mm)
Height 5.90 inches (150mm)

Information courtesy of Heckler and Koch