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 r ...

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 5th largest in the Uni ...

for the

United States Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, ...

. 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 hydraulically, electrically, or pneumatically driven, six- barrel, air-cooled, electrically fired Gatling-style rotary cannon which fires rounds at an extremely high rate (typically 6,000 rounds per minute). The M61 and i ...

. 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 1500 rounds per minute. Designed for use in combat helicopters, the XM301 boasts a dispersion of 2.2

milliradian A milliradian ( 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 firearm sights by adjusting t ...

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 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 surface (see Geodetic datum § ...

and ±120°

azimuth An azimuth (; from ar, اَلسُّمُوت, as-sumūt, the directions) is an angular measurement in a spherical coordinate system. More specifically, it is the horizontal angle from a cardinal direction, most commonly north. Mathematical ...

. 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. 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 land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cl ...

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

References

{{Reflist

External links

General Dynamics Ordnance and Tactical Systems XM301 page

XM301 Gatling Gun
at

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Rotary cannon Aircraft guns Anti-aircraft guns of the United States Multi-barrel machine guns 20 mm artillery Multiple-barrel firearms