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General Dynamics XM312

2004 MODERN

General Dynamics XM312 History

At one point, the General Dynamics XM312 was developed to replace the old and long-serving but aging Browning M2HB heavy machine gun used by the US military. Design work was led by General Dynamics under the Joint Services Small Arms Program, which began in 2000, culminating in a working prototype in 2004. The XM312 is intended for use with the proposed XM307 "Advanced Crew Service Weapon" (ACSW), a 25mm ribbon grenade launcher. The XM312 will be the new attempted 12.7mm (.50 BMG) heavy machine gun assembly, as both are equipped with common components, allowing for conversion of either system to the other with some crew modifications. In this way, the combined arms system will be logistically convenient for the U.S. military in the long run.

However, both the XM307 and XM312 were canceled as the U.S. military concentrated its efforts on procuring the proven Browning M2 machine gun and Mk 19 automatic grenade launcher - cheaper solutions at the time.

There is no doubt that the XM312 is a futuristic weapon and the next logical evolution of the heavy machine gun platform. The weapon's physical characteristics include a smooth contoured receiver with a molded casing. The barrel protrudes slightly from the fairing and the muzzle brake is noticeably missing. Ammunition is delivered via a belt mounted in a hard box on the left side of the receiver and ejected through an opening on the right side. Aiming is achieved via a flip-up assembly on the rear of the receiver or via (optional) optics that significantly improve distance accuracy.

The weapon is usually mounted on a heavy duty adjustable tripod or vehicle trunnion. The entire weapon system weighs 52 pounds and has a barrel length of 61.4 inches and a barrel length of 36 inches.

A standard operator consists of two employees - one for fire and another for ammunition supply, helping to clear stoppages and replace overheated barrels if necessary.

The XM312 initially relied on a gas and recoil system. The gas drives the bolt as the recoil action controls the advance. When this proved unreliable in testing, the weapon was assumed to operate with full recoil (as in the Browning M2). The action allows a cyclic rate of fire of 260 rounds per minute, which can be achieved with 40 rounds of continuous action before the barrel needs to be replaced.

The maximum range during the test was 2000 meters.

Like the XM312, the General Dynamics XM806 - another 12.7mm machine gun introduced in 2009 - cannot replace the famous Browning M2 series. This development was cancelled in 2012.