M6A magnum
From Halopedia, the Halo wiki
The M6A handgun is a standard issue United Nations Space Command firearm.[1]
Background
The M6A is a variant of Misriah Armory's M6 series of pistols, and is noted for its comfort. By 2552, it has been largely phased out of military use and only sees widespread distribution in civilian security forces.[1]
The M6A fires 12.7mm x 40 projectiles, and has a black polymer finish. Unlike other models such as the M6D or the M6G, it is not upsized to fit MJOLNIR armor.[2]