XM312

General Dynamics Ordnance and Tactical Systems · Machine Gun · Prototype · 2005

Also known as: XM-312, ACSW machine gun variant

Overview

The XM312 is an American prototype heavy machine gun chambered in .50 BMG, developed by General Dynamics as a lightweight, low-recoil replacement for the aging M2 Browning. Weighing roughly 16 kg, it uses a hybrid gas-and-recoil operating system that fires at a deliberately slow cyclic rate of about 260 rounds per minute, yielding far less recoil than the M2 and allowing accurate suppressive fire out to 2,000 meters. It was designed to be convertible to the XM307 Advanced Crew Served Weapon 25 mm grenade launcher with only a small number of parts swapped in the field.

Specifications

Weight (empty)16000 g (564.4 oz)
Action TypeGas Operated
Firing MechanismOpen Bolt
Magazine TypeBelt
Muzzle Velocity890 m/s (2920 fps)
Muzzle Energy16600 J (12244 ft·lbf)
Effective Range2000 m (2187 yd)
Rate of Fire260 rpm
Barrel RiflingRight Hand
Frame MaterialSteel
Barrel MaterialSteel
FinishPhosphate

Calibers

Features

Service history

Operators

Production

Production years: 2005-2008

Prototype / developmental program; never mass-produced or fielded

Origin

Country of origin: United States

Designer: General Dynamics Armament and Technical Products

Discontinued: 2008

Notes

The slow cyclic rate and hybrid action gave the XM312 dramatically reduced recoil compared to the M2 Browning, enough to be fired accurately from a lightweight tripod. The program did not enter mass production; its goals were later pursued through the lighter XM806 (LW50), which was itself cancelled in 2012.

Background

The XM312 shared a common architecture with the XM307 25 mm Advanced Crew Served Weapon, so a single weapon could be converted between a .50-caliber machine gun and a 25 mm airbursting grenade launcher at unit level in a few minutes.