From Halopedia, the Halo wiki
The M413 heavy machine gun is a twin-barrelled heavy machine gun employed by various Human military forces. The weapon is employed on the MV-29 Wyvern gunship used by CMA Marine Corps air cavalry units, the Gao Republic Ministry of War's battle-jumpers and the UNSC Army.[1]
AIE-486H • HMG-38 HMG • M199 HMG • M231 MMG • M247 GPMG series (M247H (Etilka) • M247T • M247 GPMGT) • M328 LMG • M413 HMG • M43 HMG • M67 LAW • M739 SAW (Appetite for Destruction • The Answer) • Sawtooth chaingun