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Terminal.png This article, M556 Counter Defilade Grenade Launcher, was written by Ajax 013. Please do not edit this fiction without the writer's permission.
M556 Airbursting Grenade launcher
Production information

Grenade launcher

Technical specifications


Damage Per Hit

medium to high

Magazine Size

7 shells

Fire Mode


Ammunition Type

25x40mm grenade


Gas System

Rate of Fire


  • pinpoint accurate to 600 metres
  • area accurate to 750 metres

1200 metres


United Nations Space Command


The M556 Counter Defilade Grenade Launcher is a UNSC infantry weapon frequently utilized to kill or injure hostile forces sheltered behind or in cover inaccessible by normal infantry weaponry (i.e. foxholes, trenches, concrete barriers). As its name suggests, it fires airbursting 25mm grenades, fused to explode above and slightly behind the target's position, a feature which makes it extremely effective when used against light-armoured infantry.


The M556 CDGL is a bullpup weapon and is made from a mixture of titanium alloy and polymer casing, giving a light, but tough weapon. The barrel is made from heat resistant carbonized metal, with a doppler cooling bank underneath the barrel. This cooling pack captures heat from the barrel and cools it via the doppler effect, leaving the barrel at near room temperature, also serving to double it against frost and cold. The carbon fibre insert provides heat resistance without compromising accuracy or velocity. The gun is fitted with a simple safe/fire beaver tail safety switch, giving ambidextrous control without removing a hand. The grenade launcher uses a reinforced gas reciprocation system to deal with the recoil involved in firing the weapon. When fired, the bolt travels down the receiver rather than backwards to absorb recoil and direct it away from the shooter.

The gun is fitted with four Misriah Rails, with one along the receiver, two on either side of the barrel and one underneath it. This allows the operator to fit combat sights, grips, flashlights and laser designators. However, without a Fire Control Sight, the weapon is only good as a direct fire system.

The Fire Control Unit gives the M556 point-accurate fusing on grenades, allowing the users to accurately detonate grenades at a predesignated range. The telescopic sight includes range finder, fusing settings and night vision capabilities, allowing the user to get the grenade to detonate anywhere, regardless of light conditions.

The gun has a number of cooling systems and anti-recoil systems, allowing the gun to be operated constantly and accurately. When fired, the bolt travels down the receiver rather than backwards to absorb recoil and direct it away from the shooter.


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The M556 fires a wide range of munitions: HE grenades, Thermite shells, incendiary rounds, concussion rounds, flare shells and HEAT shells, all of which, as previously mentioned, have the secondary feature of air bursting in conjunction with the fire control system.


The M556 is issued to at least one team in every squad, being used by the grenadier, though more may be issued should the need arise. The M556 CDGL is utilised when fighting enemy using plentiful 'hard' cover, such as rocks, reinforced buildings, barricades, parapets, bunkers, trenches etc. The M556 allows a squad to engage these positions from range and force the enemy out of them, allowing them to flush the enemy out of well defended positions without a costly storming manoeuvre.

Individual and Crew Served Weaponry of the UNSCDF


M6L Personal Defence Weapon System | M57 Pistol | M98 Compact | M19 Modular Pistol

Submachine Guns

M20A Submachine Gun | M12 Special Operations Carbine | M8Z Submachine Gun

Assault Rifles, Carbines, and Battle Rifles

MA6A Individual Combat Weapon System | M2A Carbine | M81 Special Purpose Carbine | M55C Enhanced Battle Rifle

Designated Marksman Rifles

M396 Designated Marksman Rifle | M97 Special Purpose Rifle | M113 Special Purpose Rifle

Machine Guns

M397 Individual Automatic Rifle | M739C Squad Automatic Weapon | M122 Light Machine Gun | M247B2 General Purpose Machine Gun | M247H2 Heavy Machine Gun | AIE-486K1 Heavy Machine Gun | M343A3 Heavy Machine Gun | M780 Special Purpose Machine Gun

Sniper Rifles

M22 Scout Rifle System | M818D Enhanced Modular Sniper Rifle System | M1091 Sniper Rifle System | Sniper Rifle System 99G-S6 Anti-Materiel | M99CA1 Special Application Scoped Rifle | M133 Precision Anti-Materiel Energy Weapon System


M45F Close Assault Weapon System | M108A1 Close Assault Weapon System | M77 Extreme Close Quarters Combat System

Energy Weapons

Weapon/Anti-Vehicle Model 6B Grindell/Galilean Nonlinear Rifle | MX4 Light Support Weapon | M921 ARC

Non-Lethal Weapon

M2 Threat-Negation Device | MX9 Pulsed Energy Projectile System | M39 Long Range Tranquillizer Rifle

Missile and Rocket Launchers

M41B2 Medium Anti-Vehicle/Assault Weapon | M899 Light Anti Armour Weapon | M57 Light Multipurpose Assault Weapon | M1 Multiple Launch Rocket System | M25 Underslung Rocket Launcher

Grenade Launchers

M319N Individual Grenade Launcher | M23 Multiple Grenade Launcher | M363B RPD | M460C Automatic Grenade Launcher | M556 Counter Defilade Grenade Launcher | M24 Underslung Grenade Launcher | M26 Grenade Launcher Module


M71 Mortar | M78 Mortar | M81 Mortar


M117 Light-Weight Field Howitzer

Sentry Guns

M55 GUARD DOG Sentry Gun | M601 GARGOYLE Sentry Gun


M9 Dual Purpose/High Explosive Grenade | M2 Anti-Materiel Grenade | M70 Flash Bang Grenade | M43 Smoke Grenade

Anti-Personnel and Anti-Armour Mines

M320 Anti-Tank Mine | M341 Anti-Tank Mine | M362 Anti-Tank Mine | M121 Bounding Anti-Personnel Mine | M127 Anti-Personnel Mine

Explosive Devices

C-7 Foaming Explosive | C-13 Gertex | C-14 Plastic Explosive | C-15 Liquid Explosive | M303 Thermite Cord | M311 Detonation Cord | M382 Special Munition Attack Charge (Kinetic) | M390 Breaching Charge | M394 Clearance Charge | M404 Special Lightweight Attack Munition | M366 Demolition Charge | M376 Satchel Charge | M379 Explosive Pack

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