M655 machine gun

From Halopedia, the Halo wiki

M655 machine gun
The Mantis' primary machinegun.
Production overview


Rotary machine gun


Ammunition type:


Feed system:


Service history

In service:

Post-Covenant War conflicts


The M655 Heavy Machine Gun/Anti-Matériel is a 20mm heavy machine gun used by the UNSC.[1][2][4]


Design details[edit]

The M655 machine gun is a rotary autocannon employed by UNSC forces. The weapon boasts four barrels fed by two 20mm ammunition belts.[3][1][2] When firing, the weapon takes a few seconds to "spool up", with the fire rate increasing rapidly over the course of a few seconds.[3]


Some variants of the Mark IX Mantis powered exoskeleton are armed with an M655 as well as an M5920 missile launcher.[1][2] Specially-upgraded Mantis variants employed by the Office of Naval Intelligence security forces employ an M655 upgraded with improved heat sink shrouds, allowing the weapon to fire for longer before overheating.[5] Mantises modified by Isabel for use by UNSC Spirit of Fire forces in the Second Ark Conflict saw the M655's lower housing removed and replaced with a large drum magazine.[6]


In Halo 4, the M655's barrels do not spin when the weapon is fired.


List of appearances[edit]


  1. ^ a b c d Halo Waypoint, Halo 4 Interactive Guide - Vehicles: Mantis (Retrieved on May 1, 2013) [local archive] [external archive]
  2. ^ a b c d Halo 4: The Essential Visual Guide, page 111
  3. ^ a b c Halo 4, M655 in-game model
  4. ^ Halo Encyclopedia (2022 edition), page 146
  5. ^ Halo 5: Guardians, REQ card: ONI Mantis description "ONI Mantis units use multi-environment homing missiles and better heat sink shrouds for the heavy machine gun. Advanced Mantis with heavy armor and upgraded weapons."
  6. ^ Halo Wars 2, Phoenix Logs: Mantis