Dillon Aero

Dillon Aero, Inc. is the manufacturer of the Air Force GAU-2B/A (Army M134) 7.62mm minigun. The company and production facility is located in Scottsdale, Arizona. Dillon is owned by Mike Dillon, the owner of Dillon Precision, a manufacture of reloading presses and other reloading equipment.

Overview
The U.S. Government had procured some 10,000 miniguns during the Vietnam War. By 1975, production of support parts had ceased with the Army in possession of such a large inventory. By 1985, there were few spares left in the inventory. Units that received them could not maintain them, so by the 1990s only Task Force 160 and some Navy Special Boat Units kept them in regular use. Around 1995, TF 160 began acquiring spare miniguns solicited by TACOM. Industry had a difficult time reproducing parts according to the original blueprints, so models that were being procured were mechanically unreliable and mixed with the inventory of working spares. This resulted in using a mixed batch of working and unreliable weapons. This fact was unknown to the 160th SOAR, and the use of miniguns that would not work shook their confidence in the system. The 160th were on the verge of dropping it from their inventory entirely, which would essentially have ended its service life in the U.S. Military.

Around 1990, Dillon Aero acquired a large number of miniguns and spares from "a foreign user." The guns kept failing to shoot continuously, revealing that they were actually worn-out weapons. The company decided to fix the problems they encountered, rather than simply putting them into storage. Fixing failure problems ended up improving the minigun's overall design.

Dillon's efforts to improve the minigun reached TF 160, and they were invited to Fort Campbell, Kentucky to demonstrate their products. A delinker, used to separate cartridges from ammunition belts and feed them into the gun housing, and other parts were fired on Campbell test ranges. The 160th SOAR liked the delinker's performance and began ordering them by 1997. This prompted Dillon to improve other design aspects, including the bolt, housing, and barrel. From 1997-2001, Dillon Aero was producing 25-30 products a year. In Fall 2001, they were working an a new bolt design that increased performance and service life, when the September 11th attacks occurred. By 2002, virtually every component of the minigun had been improved, so Dillon began producing entire weapons with their improved components. The guns were purchased quickly by the 160th Regiment as their standardized weapon system. TACOM bought several guns to go through their approval process and in 2003 the Dillon Aero minigun was certified and designated as the M134D.

Designs
The core of the M134D was a steel housing and steel rotor. To focus on weight reduction, a titanium housing and rotor were introduced, creating the M134D-T. This reduced weight from 62 lb to 41 lb. The gun housing had a 500,000 round lifespan before it wore out, which was higher than a conventional machine gun's 40,000 round lifespan but was a reduced time for a rotary gun. A hybrid of the two weapons resulted in the M134D-H, which had a steel housing and titanium rotor. It was cheaper with the steel component, was only 1 pound heavier than the M134D-T, and had an increased lifespan of 1.5 million rounds. The M134D-H is currently in use on various 160th Regiment platforms.

Minigun use
Dillon has put considerable work into creating specialized mounts and ammunition-handling systems. Initially, mounts were only made for aviation systems. Then from 2003-05, the Navy began mounting Dillon miniguns on specialized small boats. In 2005, the Naval Surface Warfare Center Crane Division procured guns to mount on Humvees. Army Special Forces on the ground in Iraq were being engaged daily, so they mounted M134Ds on vehicles. When attackers ambushed, they were hammered by the miniguns and quickly broke off the attack. Radio chatter from the enemy showed they were confused about this new weapon and told not to attack. Soon after the group equipped with Dillon miniguns were not being engaged, while other units still were. They took to concealing their new weapons to trick the enemy since they were not in the fight because the enemy was too afraid to confront the minigun and would not attack. As a further testament to the minigun's physiological effect, regular Army units began painting and tying together six sections of PVC pipe to make insurgents think they were armed with it to dissuade them from attacking.