Defense Media Network

The Evolution of the M134D Minigun

One iconic weapon system with deep historical ties to special operations forces (SOF) is the multi-barreled “Gatling gun.” Originally applied on fixed-wing and rotary-wing aircraft platforms, the “Miniguns” have evolved and expanded to a variety of naval surface and ground vehicle platforms within the SOF community.

The primary Minigun weapon system employed in SOF air, naval, and ground applications today is the 7.62 mm M134D weapon system family manufactured by Dillon Aero, in Scottsdale, Ariz.

“John Gatling came up with the Gatling gun back in the 1860s,” explained Chris Dillon, vice president at Dillon Aero. “That design was successful in its time, but then died around the turn of the [20th] century when the machine gun came out. But sometime after the machine gun came out – before or right around World War I – somebody actually took an early generation electric motor and put it on a Gatling gun. They tried it, thought it was great, didn’t know how to feed it, so put it away.”

Dillon m134d minigun

A Dillon M134D on board a Canadian CH-146 Griffon helicopter over Afghanistan. Photo courtesy of Dillon Aero

“After World War II, when the speeds of aircraft started to exceed 450 to 500 miles an hour, people realized that existing weapons didn’t produce enough concentrated fire to put a dense enough shot group into a chunk of airspace in a timely fashion,” he added. “So the government contracted with General Electric to create what was eventually called the M61 [Vulcan] Gatling gun. That is a 20 mm cannon that is in every F-16, F-18, and F-15 flying today.

“After the success of the M61, they generated lots of different designs: 30 mm guns, 25 mm guns, and during the Vietnam War, with government money, they produced the original GAU-2A and GAU-2B [7.62 mm] versions of the weapon system,” Dillon continued. “That was originally done with U.S. government money, and they produced some 10,000 guns throughout the war.”

“Sometime around 1975 they basically stopped producing any support spares for the weapon system,” Dillon stated. “That was fine, because the Army had a massive amount of inventory, which they managed to burn through over the next 10 years or so, so that essentially by 1985 there was very little spares support left in the inventory. Rapidly, units that were using the weapons found themselves unable to maintain them, so that by about the 1990s there were really only two units left using the weapon system: TF [Task Force] 160 [which evolved into the 160th Special Operations Aviation Regiment (SOAR), the “Night Stalkers”] and some of the Navy’s Special Boat Units.”

According to Dillon, the company began working with the weapon system in the ’89-’90 time frame, “completely unaware of what the military was doing with it.” Dillon Aero’s efforts began with the acquisition of a tractor-trailer load of Miniguns and spares from what he described as “a friendly foreign user.”

“So we started shooting them. And what we found in shooting them was that they didn’t work worth a darn. We tried and tried and tried to get them to shoot continuously and successfully without failures. But what we did not know at the time was that the surplus we had bought was actually worn out stuff,” he said.

“That turned out to be a blessing in disguise,” he said, “because when we got fed up with these things, we came to the conclusion that we were either going to box them up and forget about it or we were going to fix it. We chose to fix it. And in the process of solving all the problems that we discovered with the guns, we ended up fixing innate problems the gun had in its design. And knowledge of that effort eventually leaked its way back to TF 160.”

Dillon continued, “At this time – about ’94-’95 – the 160th was acquiring spares that TACOM [U.S. Army Tank-automotive and Armaments Command] was soliciting from industry. So you had these small production runs and some of it went to small ‘mom and pop shops’ that had a really hard time producing the parts to the [blueprints]. What happened was that the Army unintentionally began procuring spares that basically didn’t work. And those spares were getting into the inventory system and mixed with the existing spares that were good – essentially polluting the spares pool. The result was that guys ‘at Regiment’ [the 160th SOAR] would be putting spares in the gun and it wouldn’t work. Then they would pull another spare out, put it in the gun, and it would work. Nobody was sure what was going on but they knew they had an unreliable system now: a system that was essential to their work yet was unreliable.

Prev Page 1 2 3 Next Page


Scott Gourley is a former U.S. Army officer and the author of more than 1,500...