The 5.56×45mm cartridges are the NATO standard ammunition primarily used in carbines, assault rifles and the M249 Squad Automatic Weapon. The first version of the round was developed from the older .222 Remington round in the late 1950's. Soon after, the AR-15 and the new bullet were adopted by the U.S. Army as the M16 and 5.56×45mm M193. In the early 1980's the bullet design was updated by Fabrique Nationale in order to improve the reliability and lethality of the M16. This resulted in the M16A2 and the 5.56x45mm NATO round.
The 7.62×51mm cartridges are NATO standard ammunition, used primarily in medium machine guns and sniper rifles in all branches of the U.S. military. The family of 7.62mm ammunition consists of ball, tracer, armor piercing and dummy cartridges.
The 12.7×99mm, often referred to as .50 caliber cartridges are NATO standard ammunition, used primarily in heavy machine guns and anti-materiel rifles in all branches of the U.S. military. The family of .50 caliber ammunition consists of ball, tracer, armor piercing, incendiary and dummy cartridges, among others.
The 9×19mm Luger/Parabellum is one of the most popular pistol and submachine gun cartridges in the world. The cartridge is used in standard issue sidearms, including the M9 Beretta, the SIG Sauer M17 and M18 handguns, as well as the MP5 submachinegun.
The 20×102mm cartridges are used in the M61 Vulcan and the M197 Gatling Gun. These rounds include target practice, armor piercing, high explosive incendiary rounds, as well as ammunition for the C-RAM and the Phalanx CIWS.
The 25mm rounds are used in the M242 Bushmaster weapon system. These rounds were developed by Oerlikon in Switzerland in the 1960s.
The 30×113mm cartridges are used in the M230 Chain Gun. These cartridges include high explosive dual purpose and target practice rounds.
30×173mm cartridges are used by the Mk44 Bushmaster II and the GAU-8 Avenger Gatling Cannon. The family of rounds include, among others, target practice, high explosive incendiary, programmable air burst munitions and Depleted Uranium penetrator cartridges.
The 40×46mm Low-Velocity grenades are used with handheld grenade launchers, such as the M203, the M320 or the M32 Multiple Grenade Launcher. The types of grenades include, among others, high explosive, illuminating, smoke, non-lethal and target practice rounds.
The 40×53mm High-Velocity grenades are used with mounted or crew-served grenade launchers, such as the Mk19 or the Mk47 Grenade Machine Guns. The types of grenades include, among others, high explosive and target practice rounds. These rounds are linked together with a metallic disintegrating-link belt.
40×311mm rounds are used with the L/60 Bofors cannon.
The 57×438mm ammunition is used for the Bofors L/70 naval gun system, on which the Mk-110 is based on. Its family of ammunitions include the high explosive fuzed cartridge, guided cartridges, as well as training rounds.
The 60mm mortar cartridges are designed for use with the M224 lightweight company mortar system (LWCMS) in all light infantry battalions including Airborne, Air Assault and Ranger.
The 81mm mortar rounds are designed for use with the M252 81mm Light Battalion Mortar System, currently fielded to all Light Infantry units in the U.S. armed forces.
105mm rounds in the U.S. military are used by the M1128 Stryker Mobile Gun System vehicles.