Something almost no one knows about the A-10 Warthog’s GAU-8/A Avenger is that the initial Gun design was too precise, and they destabilized it a little to get more bullet dispersion.
Installed in all production A-10 attack aircraft as well as in both YA-10As (in which was retrofitted replacing the Vulcan cannon originally installed), the seven-barrel GAU-8/A Avenger 30 mm Gatling gun is the primary Warthog weapon for close air support (CAS) missions.
The GAU-8 itself weighs 620 pounds (280 kg), but the complete weapon, with feed system and drum, weighs 4,029 pounds (1,828 kg) with a maximum ammunition load.
It measures 19 ft 5 1⁄2 in (5.931 m) from the muzzle to the rearmost point of the ammunition system, and the ammunition drum alone is 34.5 inches (88 cm) in diameter and 71.5 inches (1.82 m) long.
Power for operating the gun is provided by twin hydraulic motors pressurized from two independent hydraulic systems.
The magazine can hold 1,174 rounds, although 1,150 is the typical load due to the 575 round capacity of the loading cart. Muzzle velocity when firing Armor-Piercing Incendiary rounds is 1,013 m/s, almost the same as the substantially lighter M61 Vulcan’s 20 mm round.
Something almost no one knows about the Avenger is that the initial Gun design was too precise, and they destabilized it a little to get more bullet dispersion.
‘As the story goes, the initial design of The Gun was a bit too precise. There wasn’t enough bullet dispersion at the impact point when fired from the optimum distance (which I assume meant 4,000 foot slant range).
‘So, the engineers tweaked the design to destabilize The Gun just enough to get the desired “5 mil, 80 percent”, meaning that 80 percent of rounds fired will hit within a cone with an angle of five milliradians; this equates to a 40-foot (12-meter) diameter circle at the weapon’s design range of 4,000 feet (1,200 m).
‘In case you are wondering why you would want more bullet dispersion, remember that this weapon isn’t like a sniper rifle. You have to maneuver 20 tons of steel, jet fuel, and high explosives through the air to point The Gun at the exact right spot for your altitude and airspeed, and then keep The Gun pointed at the target while it spews forth about 60 pounds worth of ammunition every second, with 10,000 pounds of recoil, all from about a mile away from your target.
‘In short… you want to spread your little gifts around an area to increase the odds that one of them will arrive at its intended destination. The design wizards crunched the numbers, and then played with the design until they got what they were looking for.’
‘And the result is an enduring piece of destructive engineering magic.
Photo credit: U.S. Air Force