Battle rifle

There are two references to Battle Rifle in the Halo Universe:


 * Prototype BR-55 - Halo: Contact Harvest-prototype Battle Rifle
 * BR55 Battle Rifle - Halo 2-era Battle Rifle
 * BR55HB SR Battle Rifle - Halo 3-era Battle Rifle

Or were you looking for the Particle Beam Rifle, the Covenant Sniper Rifle (if you typed "BR")?