A drum magazine stores ammunition efficiently and still allows extremely rapid feeding to the weapon It is generally flexible and may allow empty casings to be stored back in the magazine.
Only its muzzle of its seven (7) 30mm barrels poke through the nose of the A-10. To aim at the target the whole aircraft must point at the target.
At left is the body of an A10 showing the arrangement of the Avenger weapon system. The hollow zone besides the gun is for the forward landing gear.
The linkless drum magazine employs a spiral arrangement of the rounds. The body of the magazine features longitudinal "channels" whereas the inner rotor features a spiral grove. As it rotates, the channels force the rounds to go straight towards the face of the drum.
The differential ammunition buffer mounted on the face of the magazine serves two purposes. The first is to get the rounds from each linear channel of the magazine as they slide forward, and the second is to adapt the speed of the ammunition feeder to the firing rate of the Gatling, which varies due to progressive acceleration when firing commences.
The feeder is mounted on the buffer, it uses sprockets to engage the ammunition rounds and thrust them in the feeder chute. The feeder chute in the A10 the gun is fixed and is not flexible, for greater reliability. The feeding system is bi-directional, which allows to store-back fired ammunition (empty cases) and to unload or reload the gun from a port on the side of the plane.
A gear box between the gun and magazine to provide motion to both.
The photo at left illustrates reloading a a GAU-8 Avenger Gatling gun. 1500 rounds of extremely heavy ammo cannot be expedited manually so a loader is used. It is a device that is much like another magazine except that it is intended to feed the on-board magazine of the gun. It also extracts used or unfired ammo.
Looking down the barrel of a GAU-8 Avenger
For size comparison, the 30mm round above exits the barrel of the gun (below).
Hello, my name is Richard Jordan Gatling. You may know of me because of my least favorite invention, the Gatling Gun. If you would like to visit me, I am buried at Crown Hill Cemetery, Indianapolis, Indiana. [So many good things come out of Indiana, like Charles Manson. Remember him?]
I was born in he year 1818, on my father's plantation. While still in my teen years, I helped my father, Jordan Gatling, invent two machines. One was for sowing cotton, the other was for thinning young cotton plants. In 1839, at the age of 21, I invented a steamboat screw propeller. However, another person had patented it only months earlier. Later that year, I completed my seed-sowing rice planter, which I later adapted to the wheat drill. The wheat drill made me a wealthy man in the later years of my life. In the 1840s, an outbreak of smallpox left me interested in medicine. I attended Ohio Medical College, and graduated in 1850. After graduating, I soon lost interest in medicine, and instead of entering a medical practice, I decided to continue my career in the field of inventing. For the next few years I continued to invent and improve upon my inventions. In 1857, I invented the steam driven plow. Although I patented the plow, it was not well accepted by farmers and failed to show me much of a profit. Following the outbreak of the Civil War, I turned my attention to the invention of firearms. By 1862 I had completed and patented the Gatling Gun, making it my eleventh patent. The gun was rapid fire, hand-cranked, and solved the problem of sustained loading and firing. I was 44 at the time, and I spent the rest of my life improving and living off the monetary benefits of the Gatling Gun. Although I have been named a hypocrite by those that consider me a pacifist, I intended for the gun to save the lives of the user, not to take mass amounts of life. Another reason for being named so is the sympathy I felt towards the Southern cause. I worked to improve the gun for many years following the Civil War, and after many years of partnership, the Gatling Gun Company merged with the Colt Patent and Fire Arms Manufacturing Company. When I died in 1903, my fortune was smaller than it should have been, a result of failed real estate sales and unsuccessful railroad deals.
The first Gatling Gun had six barrels that revolved around a central shaft. The gun used the expensive .58 caliber paper cartridges. A barrel were loaded when it reached the top of it's rotation. At the top, a bullet was dropped into it. When it reached the bottom of it's rotation, the bullet was fired. By 1865, I had changed the gun so it fired a unitary cartridge, also known as a metal cartridge. Even though the Gatling gun was used in limited engagements during the Civil War, it wasn't until 1866 that the Army officially adopted the Gatling Gun. The U.S. Navy had adopted the gun in 1862, and had many on it's ships. In it's first order, the army bought 50 one inch caliber guns, and 50 .50 caliber guns. Soon after buying the guns, all but five of the .50 caliber guns were converted to the standard .45 caliber bullet. The Gatling Gun went through many changes, like changes in number of barrels, size of bullet, type of bullet magazine. In later models, guns were made smaller, to allow the gun to be mounted not on an artillery carriage, but on a tripod. The guns were still mounted on carriages, but the carriages were much improved, allowing the gunners to sweep the field during a battle. The guns were also able to be adjusted for storage, with the gun being able to move up and down. Parts of the gun were painted at times, and the type and amount of paint on guns can determine the model of most Gatling guns. The Gatling Gun was used in many wars, both domestic and foreign, before the gun was declared obsolete in 1911. The war the gun saw it's first major action in the Spanish-American War. In the war, the gun was used in close support of the American troops, often being pushed up a hill while still being fired. The U.S. Army's use of the Gatling Gun in the Spanish -American War gained the gun much in the way of notoriety. As a result, many other nations bought and used the gun. During the late 1890s, I attached an electric motor to a few experimental models. Those models achieved a rate of fire that exceeded 3,000 shots per minute, a far cry from the original 200 shots per minute. The ideas behind the Gatling Gun were unused until the 1950s, when the machine guns of the day had rates of fire slower than most models of Gatling Guns. Arms designers then developed the Vulcan Gun, a three barreled machine gun that used most of the basic principles of the Gatling Gun. The Vulcan Gun is still used on helicopters and planes today and can destroy heavily armored vehicles like tanks.