Rifle

A Rifle is a handheld firearm firing from an "intermediary" cartridge, heavier than a Carbine, but lighter than a Battle Rifle (which has a "full" cartridge" ), and often firing projectiles of some form of matter in a direct linear trajectory.

There are twelve appearances of "rifle" in the Halo universe:

HMG series

 * HMG-38 Rifle - an older rifle no longer used by the UNSC, presumably an assault rifle

MA series

 * MA2B Assault Rifle - a stripped-down variant MA5B assault rifle
 * MA3 Assault Rifle - an earlier version of the MA-series assault rifles
 * MA5B Assault Rifle - the most common MA-series rifle, featured in Halo: Combat Evolved.
 * MA5C Assault Rifle - newer version of the MA5B rifle, featured in Halo 3.
 * MA5K Assault Rifle - uncommon MA-series rifle wielded by special operations groups such as the SPARTAN-IIIs

Battle Rifles

 * BR55 Battle Rifle - two-handed firearm firing in 3-round bursts featured in Halo 2
 * BR55HB SR Battle Rifle - an updated version of the BR55 for Halo 3

Nonlinear Rifles

 * Anti-Vehicle Model 6 Grindell/Galileian Nonlinear Rifle (W/AV M6 G/GNR) - shoulder-mounted anti-vehicular directed laser weapon featured in Halo 3

Sniper Rifles

 * SRS99C-S2 AM Sniper Rifle - long-range two-handed projectile weapon
 * SRS99D Sniper Rifle - Halo 3-variant of the SRS99C-S2 AM Sniper Rifle

Particle

 * Particle Beam Rifle - long-range two-handed weapon, analogous to the UNSC SRS99C-S2 AM Sniper Rifle

Plasma

 * Plasma Rifle - one-handed plasma-operated weapon typically wielded by Sangheili (Elites)
 * Brute Plasma Rifle - variant of the standard plasma rifle wielded by Brutes.