United States
0.30 caliber (7.62 mm) Minigun
Air Force - GAU-2B/A
Navy - GAU-17/A and GAUSE-17/A
Army - M134
Updated 20 February 2009
 Developed by General Electric in the early 1960s, the "Vulcan" series of miniguns is available in many calibers from 5.56 mm (0.223 in) up to 25 mm (1.0 in).  The 0.30 caliber (7.62 mm) GAU-2 version was first deployed by the Air Force for use on light aircraft and helicopters, but has since been adopted by the Army, Marines and Navy for the same purposes.  These guns are widely used, with the U.S. Army alone purchasing over 9,500 M134 guns.  In the last few years, the Navy has started using these weapons on ships to supplement the 25 mm Chain Gun and venerable 0.50 in "Ma Deuce" M2 BMG.

The term "Vulcan" was originally the GE Project Name for the first Gatling-type electric-powered minigun and is now a slang term for all of these electric Gatling guns.

The GAU-17/A gun system consist of a six-barrel rotary gun, a gun control assembly with electrical cables, gun drive motor unit, a delinking feeder, flexible ammunition feed chutes and an ammunition storage system.  Gun component parts, such as the rotor, housing, feeder/delinker, and barrel clamp/flash suppressor, are available in either steel or lightweight titanium.

Quoting from a USMC HMLA OAG Action Item:  "The GAU-17 minigun, while providing [an] outstanding volume of fire, is notorious for jamming."  Most of the problems occur in the Feeder/Delinker assembly.  One manufacturer of this weapon, Dillon Aero, Inc., claims its Feeder/Delinker is much more reliable with an average of 30,000 rounds between stoppages.

This weapon is also used on surface warships in the British Royal Navy.
WNUS_30-cal_GAU17_minigun_pic.jpg

0.30" (7.62 mm) M134D Gatling Gun
Photograph copyrighted by Dillon Aero, Inc.
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Click here for additional pictures
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Gun Characteristics
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Designation
(see Note 2)		 Gun - M134D
Aircraft - GAU-17/A
Ships - GAUSE-17/A
Ship Class Used On Many
Date Of Design about 1963
Date In Service 1965
Gun Weight 35 lbs. (16 kg)
Gun Length oa 29.5 in (75 cm) including suppressor
Barrels are 22 in (55.9 cm) long
Bore Length N/A
Rifling Length 20 in (50.8 cm)
Grooves 4
Lands N/A
Twist Uniform RH 1 in 33.333
Chamber Volume N/A
Rate Of Fire
(see Note 3)		 2,000 to 4,000 rounds per minute
Notes:

1) Barrel cluster rotates counterclockwise as viewed from the breech end.

2) M134D is the minigun itself.  Other designations are usually for the "gun assemblies" that include the mounting.  The GAUSE designation appears only on text released with U.S. Navy photographs.  It may represent a "sailor-alt" rather than an official U.S. Navy designation, although I have been unable to confirm that one way or the other.  I have been told by USN personnel that the "SE" in GAUSE probably stands for "Shipboard Equipment" and refers to the entire gun and mounting assembly rather than to just the minigun itself.

3) The original design of the 1960s had a fixed rate of about 6,000 rounds per minute.  This was unsustainable over any period of time and the weapon was redesigned to add a transmission housing at the motor, giving the weapon a variable speed of 2,000 or 4,000 rounds per minute.  On the newer Dillon Aero Inc. version, the rate of fire is determined by the gun drive unit used, with drive units giving either 3,000 or 4,000 rounds per minute available.  There is no speed selection on this version other than by assembling a different gun drive motor to the the gun system assembly.  The 3,000 ROF drive motor takes 0.5 seconds to spin up to speed and 0.25 seconds to spin down to stop.  When the trigger is released, there is a delay until all six barrels have been cleared by fire.  This ensures that no live ammunition is left in the firing chambers, thus eliminating cook-off problems.
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Ammunition
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Type Fixed
Weight of Complete Round Ball - N/A
Projectile Types and Weights Ball - 0.34 oz (9.65 gm)
Bursting Charge None
Projectile Length N/A
Complete Round - 2.75 in (6.99 cm)
Propellant Charge N/A
Cartridge 7.62 x 51 mm
Muzzle Velocity 2,800 fps (854 mps)
Working Pressure N/A
Approximate Barrel Life 100,000 rounds per barrel cluster
Ammunition stowage per gun Up to 4,400 rounds of ready ammunition
Notes:

1) These guns use standard NATO 7.62 mm percussion primed ammunition which is usually supplied in in 1,000 round disintegrating-link belts.

2) Magazines are available in various sizes:

   1,500 rounds:  Empty 24.4 lbs. (11.1 kg), Full 125 lbs. (56.8 kg)
   Standard 3,000 rounds:  Empty 27.0 lbs. (12.25 kg), Full 208 lbs. (94.5 kg)
   HMMWV 3,000 rounds:  Empty 24.4 lbs. (11.1 kg), Full 204 lbs. (93 kg)
   4,400 rounds:  Empty 31.0 lbs. (14.1 kg), Full 295 lbs. (134 kg)
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Range
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Elevation With 0.34 oz (9.65 gm) Ball
Maximum Range about 1,100 yards (1,000 m)
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Mount / Turret Data
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Designation Single Mountings
   Mark 16 Naval Post Mount
   GAU-17/A Aircraft Mount
Weight  Total System Weight - (less ammunition, battery and mount)
   Steel, fixed forward fire:  56.9 lbs. (25.8 kg)
   Titanium, fixed forward fire:  45.1 lbs. (20.5 kg)
   Steel, crew served: 66.1 lbs. (30.0 kg)
   Titanium, crew served: 53.13 lbs. (24.1 kg)
Elevation N/A
Elevation Rate Manual operation, only
Train 360 degrees
Train Rate Manual operation, only
Gun recoil N/A
Note:  Unit requires 24 - 28 Vdc, 58 amps to operate.  Vac power supply option is also available.
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Data from
"The Naval Institute Guide to World Naval Weapon Systems 1991/92" by Norman Friedman
"Jane's Ammunition Handbook:  Ninth Edition 2000-2001" edited by Terry J. Gander and Charles Q. Cutshaw
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"M134D Minigun Product Information Guide" by Dillon Aero, Inc.
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U.S. Army Deputy, Integrated Logistics Support Center
U.S. Navy Press Releases
USMC HMLA OAG Action Item 1997-40
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Special help by Leo Fischer
Page History

30 October 2006 - Benchmark
20 February 2009 - Corrected typographical error