The H&K M24, minus the suppressor and laser aiming module.

The M24 is a .45 caliber handgun used by the United States military. An upgrade of Heckler and Koch’s Mk23, the M24 is the standard issue handgun for Marine Vent Infiltration Specialists, or “Vent Rats”, some of whom choose to carry it as a primary weapon when infiltrating ventilation systems, fitted with an optional suppressor. It is also an option for Special Forces operators; Mark Drake and Trevor Wierzbowski of the 9th Regiment’s Reconnaissance In Force Team 1 both carried M24s, although Drake eventually returned his in favor of a Zastava M88A he captured in Romania.

Weapon Designation:Pistol, .45 Caliber, Semiautomatic, M24
Place of Origin:Germany
In Service:2054-present
Production History:
Manufacturer:Heckler & Koch GmbH
Weight:2.43 lb (1.2 kg) (plain)
4.23 lb (2.02 kg) (with suppressor and LAM)
Length:9.65 in (245 mm) (plain)
16.5 in (421 mm) (with suppressor)
Barrel Length:5.87 in (149 mm)
Cartridge:.45 H&K
Action:Short recoil
Rate of Fire:Semiautomatic
Muzzle Velocity:1,600 ft/s (488 m/s) with M45120D round
1,000 ft/s (305 m/s) with M45200P round
Muzzle Energy:682 ft/lbs (924 Joules) with M45120D fluted round
444 ft/lbs (602 Joules) with M45200P fluted round
Effective Range:50 m (55 yd)
Feed System:12-round detachable box magazine
Sights:Iron sights


Although the United States Marine Corps liked the Mk23, in the 2050s they wanted an improved design to incorporate suggestions made by field users. Heckler and Koch’s answer was the similar Mk24, which was accepted by the US military as the M24 in 2054.


The M24 is very similar to the Mk23. There are four primary changes that set the M24 apart from the Mk23:

1: The slide release lever is ambidextrous, and the two sides are held together by a screw with an oversized slot head through the pivot pin to allow for disassembly of the weapon.

2: The decocking switch has been altered to be able to rotate upwards and act as a slide block. This prevents the slide from cycling during firing, which helps to keep the weapon much quieter when fired with a suppressor because there is no open ejection port for gas to escape and because the spent casing is not ejected. This does, however, greatly limit the rate of fire, as after each shot, the slide block switch must be pushed into the downward position, the slide cycled by hand, and the slide block switch pressed up again. This also increases felt recoil significantly, because the slide does not recoil and therefore the recoil spring does not absorb any of the firing force.

3: The M24 uses a completely different suppressor and laser aiming module than the Mk23. Both were designed using the most advanced technology allowable under the Future Weapons Development Ban, and are significantly lighter and more effective than those made for the Mk23.

4: Although the M24 is capable of firing both .45 ACP and .45 Super, it is intended for use with the .45 H&K, which is nothing more than a variation on .45 Super with a slightly thicker casing. This results in lower internal capacity for propellant, but advancements in propellants allow the .45 H&K to be loaded in both a subsonic cartridge with similar performance to .45 ACP and a supersonic cartridge similar to .45 Super. The subsonic round, which weighs 200 grains, is intended for use with the suppressor and has a maximum muzzle velocity of 305 meters/second. The supersonic round weighs 120 grains, has a maximum muzzle velocity of 488 meters/second, and is intended for use when the weapon is not being used with the suppressor as the sonic boom from firing is less of an issue than when deliberately trying to be as silent as possible. However, it is entirely possible to fire the subsonic round without the suppressor or the supersonic round with it if necessary.

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