The XM301 Cannon was an externally powered, three-barrel 20 mm

rotary cannon A rotary cannon, rotary autocannon, rotary gun or Gatling cannon, is any large-caliber multiple-barreled automatic firearm that uses a Gatling-type rotating barrel assembly to deliver a sustained saturational direct fire at much greater ra ...

made by

General Dynamics General Dynamics Corporation (GD) is an American publicly traded aerospace and defense corporation headquartered in Reston, Virginia. As of 2020, it was the fifth largest defense contractor in the world by arms sales and fifth largest in the Unit ...

for the

United States Army The United States Army (USA) is the primary Land warfare, land service branch of the United States Department of Defense. It is designated as the Army of the United States in the United States Constitution.Article II, section 2, clause 1 of th ...

. Developed for use with the RAH-66 Comanche

stealth helicopter Stealth helicopters are helicopters that incorporate stealth technology to decrease an enemy's detection ability. There are a diverse range of technologies used to achieve this decreased detectability; these have largely involved the reduction of ...

, it is the world's lightest 20 mm rotary cannon. The XM301 was designed to be a versatile and accurate lightweight cannon that could serve both an air-to-air and

air-to-ground Air-to-ground weaponry is aircraft ordnance used by combat aircraft to attack ground targets. The weapons include bombs, machine guns, autocannons, air-to-surface missiles, rockets, air-launched cruise missiles and grenade launchers. See also ...

role. Development and manufacture of the XM301 was cancelled in 2004 along with its parent RAH-66 program.

Description

The XM301 is a lightweight, three-barrel version of the

M61 Vulcan The M61 Vulcan is a Hydraulic machinery, hydraulically, electrically, or pneumatics, pneumatically driven, six-Gun barrel, barrel, air-cooled, electrically fired Gatling gun, Gatling-style rotary cannon which fires 20 mm caliber, rounds at an e ...

. It is externally powered, relying on the same power delivery system as the Vulcan. It fires M50 and PGU-series ammunition found in the Vulcan, as well as newer lightweight X1031/1032 aluminum-cased ammunition at either 750 or 1,500 rounds per minute. Designed for use in combat helicopters, the XM301 boasts a dispersion of 2.2

milliradian A milliradian (International System of Units, SI-symbol mrad, sometimes also abbreviated mil) is an SI derived unit for angular measurement which is defined as a thousandth of a radian (0.001 radian). Milliradians are used in adjustment of ...

s, making it accurate at long ranges. The XM301 weighs 80.5 pounds, less than a third the weight of the Vulcan. It can hold 500 rounds of ammunition and is able to be field-reloaded in 15 minutes. The turret allows an aiming range of +15° to -45° in

elevation The elevation of a geographic location (geography), ''location'' is its height above or below a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational equipotenti ...

and ±120°

azimuth An azimuth (; from ) is the horizontal angle from a cardinal direction, most commonly north, in a local or observer-centric spherical coordinate system. Mathematically, the relative position vector from an observer ( origin) to a point ...

. It may be stored at +2° in elevation and 180° azimuth in order to reduce radar cross-section.

Development

Development on the XM301 began in 2001 as part of the RAH-66 Comanche project. Originally developed in the 1980s, the Comanche had been tested with a two-barrel version of the M61 Vulcan, but it was upgraded to a three-barrel unit before

took over the program in 2001. In its early stages the XM301 was known as the GE Vulcan II, an improved

M197 Gatling gun The M197 electric cannon is a 20 mm three-barreled electric Gatling-type rotary cannon used by the United States military. Development The M197 electric cannon was developed primarily for use by United States Army helicopter gunships. Dev ...

. General Dynamics worked in tandem with Groupement Industriel des Armements Terrestres (GIAT) to develop the primary armament system for the RAH-66, with GIAT developing the turret and General Dynamics the weapon itself. The RAH-66 first flew in January 1996 with a non-functional version of the XM301, although subsequent flights used a working development model, with development testing beginning in 1997. General Dynamics and GIAT were contracted to deliver a total of 1,217 XM301 weapon systems to the

U.S. Army The United States Army (USA) is the primary land service branch of the United States Department of Defense. It is designated as the Army of the United States in the United States Constitution.Article II, section 2, clause 1 of the United Stat ...

, but funding for the RAH-66 was redistributed to the upgrade of existing helicopters in February 2004.

References

External links

General Dynamics Ordnance and Tactical Systems XM301 page

XM301 Gatling Gun
at

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{{USAF weapons Rotary cannon Aircraft guns Anti-aircraft guns of the United States Multi-barrel machine guns 20x102mm Multiple-barrel firearms