Assault rifle

An Assault Rifle is a selective-fire firearm using a projectile with a muzzle energy in between those of a full-sized rifle and a smaller submachine-gun or a pistol. Assault rifles are categorized in between light machine guns, which are intended more for sustained automatic fire in a support role, and submachine guns, which fire a pistol cartridge rather than a rifle cartridge.

History
Assault Rifles date back to the end of the Second World War. Germany developed the first assault rifle, a weapon called the Sturmgewehr 44, although it was not used to a full extent because of its manufacturing date being so close to the end of the war, the gun was made in 1944, in an effort to provide their infantrymen with a firearm better suited to the mid-ranged engagements of modern warfare. Then came the Russian AK-47, which basically set the definition of an assault rifle. By the time of the Halo trilogy, most assault rifles also house an onboard electronics suite, showing ammo capacity, a compass, and other information, without the use of a HUD.

These could refer to the following: It is also possible that the BR55 is an Assault Rifle, as it doesn't fire a full rifle cartridge and, in trailers, seems capable of fully automatic fire hinting at a selective fire feature that was not included due to gameplay issues. In some ways the Battle Rifle is a better assault rifle than the over grown SMG, the MA5B, and its Halo 3 iteration, the MA5C.
 * MA2B Assault Rifle - The stripped-down version of the MA5B Assault Rifle.
 * MA3 Assault Rifle - The older variant of the MA5B Assault Rifle.
 * MA5 Series
 * MA5B Individual Combat Weapon System - The standard UNSC armament in from the early-2500's to 2552. It was phased out shortly after the Battle of Reach and the Battle of Installation 04. (Halo: Combat Evolved)
 * MA5C Individual Combat Weapon System - A new MA5 model introduced in late-2552 during the late Battle of Earth and the Battle of Installation 00. (Halo 3)
 * MA5K Carbine - A special version of the MA5B Assault Rifle utilized by the SPARTAN-III's and other Special Operation forces.
 * BR55 Battle Rifle - Replacing the Assault Rifle in Halo 2, despite not appearing as a complimentary weapon to the MA5B in the canon.
 * BR55HB SR Battle Rifle - Replacing the BR55 in Halo 3; it is almost identical to the BR55.
 * BR55HB SR Battle Rifle - Replacing the BR55 in Halo 3; it is almost identical to the BR55.