The GAU-19 Gatling .50 Cal is one serious piece of hardware which I thought I’d mention today in light of it’s renewed interest for Naval deployment.  Many have never even heard of it or seen it deployed, which is a shame because this monster can lay down the hate.  Whenever someone is talking about the .50 Cal BMG round, you just know it’s going to be some serious firepower being laid out.  Normally the .50 Cal BMG is associated with the M2HB heavy machine gun.  With growing piracy threats and the increased threat of waging war with Iran and their many small boats such as the old Boghammar and copies, the GAU-19 is gaining popularity as an effective defensive weapon to counter the small-boat threat.

GAU-19/A Mounted on SH-60The GAU-19, or Gun, Aircraft Unit-19 was originally designed to be utilized as the forward gun turret for helicopters (commonly referred to as the ‘chin’ gun) such as the AH-1 Cobra (The AH-1 utilized the M197 instead).  General Electric designed the weapon in the late 70s and it first saw service in 1983 under the designation GAU-19/A.  The system was once designed as a beefed up copy of the M134 7.62x51mm Minigun, complete with 6 barrels and firing the much larger .50 BMG cartridge.  Later on during testing it was decided the 6 barrel system depleted the systems magazine too quickly and added too much weight to the already large weapon, so a 3 barrel prototype was developed.  The 3 barrel version was smaller, lighter, and didn’t deplete ammunition as aggressively.

GAU-19/A External MountThe GAU-19 has seen little change made to its design since entering service.  It is still relatively unknown to the majority despite the impressive firepower it can deliver and General Dynamics now seek to see it adopted in more roles than the original design as a Helicopter only weapon.  General Dynamics created a more diverse set of mounting options in hopes to attract more sales of the system.  There are now aircraft external mounts (pods), aircraft crew mounts, vehicle mounts, and surface ship mounts available.  A recent version has been released, the GAU-19/B, which reduces the system weight and is optimized for vehicle or patrol boat usage.  With the newer system, interest is growing in the Naval Mount version in particular as a small boat defensive weapon.

GAU-19 HMMWV MountedThe system operates very much like the 7.62mm M134 Minigun system in being electrically driven and mechanically fired.  When the system is firing, a feeder/delinker is spun by the systems drive motor and strips the ammunition out of the belt before handing it off to the actual gun portion of the weapon.  Think of it like a cars serpentine belt.  The drive motor rotates the gun, and in turn rotates the feeder/delinker as well.  The ammunition feeds into the weapon as it rotates, and the 3 bolts are following a guide cam on the gun housing.  The guide cam drives the bolts forward and rearward to perform chambering, locking, firing, and then unlocking, extracting, and ejecting in a wide elliptical motion.  When the bolt is in its forward most point, compression releases the firing pin to discharge the round and is re-cocked as it is pulled rearward.   Specifications for the system are as follows:

  • Gun Weight: 138 lb for GAU-19/A or 106 lb for GAU-19/B
  • Rate of Fire:  1,000/1,250/1,300/2,000 rpm for GAU-19/A or 1,300 rpm for GAU-19/B
  • Magazine: 900 rounds (HMMWV), 1,200 rounds (Naval), 500-1,200 rounds (GAU-19/B)
  • Recoil Force:  495 lb @ 1,300 rpm (GAU-19/A HMMWV or Naval), 575 lb @ 1,300 rpm (GAU-19/B)
  • Effective Range:  2,000yds (1 Nautical Mile)
  • Max Dispersion:  5 mrads (80% circle) = 5m @ 1000m

There is a wide variety of ammunition available for the .50 BMG cartridge.  The GAU-19 system can utilize any available linked .50 BMG ammunition from standard ball and tracer, Armor Piercing Incendiary-Tracer (API-T), API-Dim Tracer, or the advanced Mk 211 variety rounds which I would encourage the use of for naval units.  The Mk211 and Mk257 rounds have been called Raufoss rounds by some since that was the name of the Norwegian city the rounds were first produced in and has been nicknamed as ‘Christmas Tree’ in some NSW circles due to the green, red, and aluminum paint markings on the tips of the linked rounds.  In technical terms, it is a High Explosive Incendiary, Armor Piercing (HEIAP) Tracer (Mk211) or Dim Tracer (Mk257).  I absolutely love this round, it makes nice big pop’s on target, often setting fires, and it makes a mess wherever it hits throwing out a 30° cone of fragmentation.  It is packed with 1 gram of RDX Comp-A Explosive for a filler, topped with .6 grams of zirconium for incendiary effect, and is pyrotechnically initiated after impact by the tungsten carbide armor piercing penetrator.  Mk211 Mod 1 (Grade B) is for machine gun use only, while Mk211 Mod 0 (Grade A) is meant for sniper applications due to being manufactured to a higher quality standard.  A video describing the round in use in a sniper application is at this link.

Standard Tracer
Regular Tracer on Night Vision
IR Dim Tracer
Firing Dim Tracer on Night Vision

In case you are wondering what a ‘Dim Tracer’ is, it is a special tracer which burns in the infrared spectrum and is invisible to the naked eye, but visible when using Night Vision Devices (NVD’s).  It produces less ‘white-out’ for gunners with NV Goggles on.


With the variety of mounts available for the GAU-19 it is receiving a more serious look for employment, primarily for the Navy as mentioned before.  The system when firing at 1,300 rounds per minute is firing 21 rounds per second and 7 rounds per barrel in that second.  If you have ever fired the M2HB, with it’s cyclic rate falling between 440-550 rpm its roughly shooting about 8 rounds in a second versus the 21 rounds from the GAU-19.  The GAU-19 can sustain fire for about a minute from its 1,200 round magazine, while the M2HB is usually holding about 200-250 rounds in it’s can on patrol boats.  Anyone who has shot the M2HB aggressively also knows that trying to empty 200-250 rounds in one burst will likely result in the weapon failing or cooking off.  The increased fire rate of the GAU-19 helps to get gunners on target faster and achieve more target impacts much like the M134 Minigun systems theory of employment.  The faster rate of fire means more rapid visualization of tracers and round impacts to drive the weapon onto the target with.  Against boats, the GAU-19 can devastate a craft if paired with the Mk211 rounds which have the potential of penetrating engines and setting fuel ablaze.  %EMBED6%

In the video above you might have noticed a sudden increase in fire rate while shooting.  That was the gunner switching from 1,000rpm to 2,000rpm.  To wrap-up this article, I do hope the system becomes more widely adopted in our own service.  While it does have some shortfalls, such as it needing a reliable 24 VDC power source to power the drive motor or the competing availability of other weapons such as 20mm chain guns, I do believe that for a manned weapon this system holds it’s own against the competition being a relatively easy system to maintain in good service compared to the competitions weapons systems.  In the threat of suicide boats or against Iranian Gun Boats this system could allow rapid engagement and destruction out to a nautical mile with common ammunition and without needing major structural changes to emplace.  Training for gunners and armorers is fairly easy and the overall system cost is low and comparable to the M134 Minigun.  Why the system hasn’t seen wider adoption is beyond me, I’ll just have to wait and see I guess.

Bravo One, Out.