30 mm caliber in the context of "Boeing AH-64 Apache"

Depleted uranium (DU), also referred to in the past as Q-metal, depletalloy, or D-38_, is uranium with a lower content of the fissile isotope U than natural uranium. The less radioactive and non-fissile U is the main component of depleted uranium.

Uranium is notable for the extremely high density of its metallic form: at 19.1 grams per cubic centimetre (0.69 lb/cu in), uranium is 68.4% more dense than lead. Because depleted uranium has nearly the same density as natural uranium but far less radioactivity, it is desirable for applications that demand high mass without added radiation hazards. Civilian uses include counterweights in aircraft, radiation shielding in medical radiation therapy, research and industrial radiography equipment, and containers for transporting radioactive materials. Military uses include armor plating and armor-piercing projectiles.

The Fairchild Republic A-10 Thunderbolt II, also widely known by the nickname Warthog, is a single-seat, twin-turbofan, straight-wing, subsonic attack aircraft developed by Fairchild Republic for the United States Air Force (USAF). In service since 1977, it is named after the Republic P-47 Thunderbolt strike-fighter of World War II, but is instead commonly referred to as the "Warthog" (sometimes simply "Hog"). The A-10 was designed to provide close air support (CAS) to ground troops by attacking enemy armored vehicles, tanks, and other ground forces; it is the only production-built aircraft designed solely for CAS to have served with the U.S. Air Force. Its secondary mission is to direct other aircraft in attacks on ground targets, a role called forward air controller (FAC)-airborne; aircraft used primarily in this role are designated OA-10.

The A-10 was intended to improve on the performance and firepower of the Douglas A-1 Skyraider. The Thunderbolt II's airframe was designed around the high-power 30 mm GAU-8 Avenger rotary autocannon. The airframe was designed for durability, with measures such as 1,200 pounds (540 kg) of titanium armor to protect the cockpit and aircraft systems, enabling it to absorb damage and continue flying. Its ability to take off and land from relatively short and unpaved runways permits operation from airstrips close to the front lines, and its simple design enables maintenance with minimal facilities.

The Mk44 Bushmaster II is a 30 mm chain gun manufactured by Northrop Grumman. It is a derivative of the 25 mm M242 Bushmaster, and uses 70% of the same parts as the M242 while increasing the firepower by as much as 50% with the 20% increase in caliber size. The barrel is chromium-plated for extended life. The gun uses standard GAU-8 Avenger ammunition that is available in API (Armor-Piercing Incendiary), HEI (High-Explosive Incendiary) and APFSDS-T (Armor-Piercing Fin-Stabilized Discarding Sabot-Tracer) variants.

The gun can be converted to a caliber of 40×180 mm, which involves changing the barrel and a few key parts, to use the SuperShot 40 cartridge. It can also be converted to use the 30×170 mm RARDEN cartridge.

The General Electric GAU-8/A Avenger is a 30 mm hydraulically driven seven-barrel Gatling-style autocannon that is primarily, and most famously mounted in the United States Air Force's Fairchild Republic A-10 Thunderbolt II. Designed to destroy a wide variety of ground targets, the Avenger delivers 30mm rounds at a high rate of fire. The GAU-8/A is also used in the Dutch Goalkeeper CIWS ship weapon system, which provides defense against short-range threats such as highly maneuverable missiles, aircraft, and fast-maneuvering surface vessels. The GAU-8/A was designed by General Electric and has been produced by General Dynamics since 1977.