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40px-Terminal.png This article, M12A1 GUARD DOG Sentry Gun, was written by Ajax 013. Please do not edit this fiction without the writer's permission.
Production information

M12A1 GUARD DOG Sentry Gun

Technical specifications
  • mass:12.1 kg
Ammunition Type


Rate of Fire

3000 rounds/minute


900 metres


1300 metres


Necros War




The M12A1 GUARD DOG Sentry Gun is a UNSC Sentry Gun.


The M12A1 GUARD DOG Sentry Gun is a remote Sentry Gun used by the UNSC. The unit weighs 12.1 kg and can be assembled by a single marine in nearly 1 minute. The unit consists of a single, self contained gun assembly which contains the sensor systems, the barrel assembly, the magazine and the fire control computer and a collapsing, motorised tripod. A radio datalink connects the sentry the UNSC War Net, where in it can be interfaced by a single Marine, A.I. or routed to a remote computer, when accessed by the correct password. Once in place, the sentry gun may be programmed to sweep wide arcs up to 360 degrees, though it is subject to terrain and emplacement restrictions, though Marine Corp doctrine is to place several sentries to cover smaller, interlocking fields of fire in a narrow band in front of it. The M12A1 GUARD DOG Sentry Gun mounts a M2Z caseless weapon, using the 6.8x32mm caseless munition. The weapon fires at 3000 rounds per minute and electronically cooled with titanium-chrome cold hammer forged barrels and carbon fibre inserts.

The sentry gun's main sensor array is mounted beside the barrel, aligned to cover a forward cone in front of the weapon. The sensor suite consists of a cooled infra-red detector, full colour day/night optics, a two stage passive infra-red/ultrasonic motion tracker and a LIDAR. If a target’s visual or thermal profile is recognised, the fire control system may be set just to monitor those specific targets using infra-red or optical. However, the system is usually set to multi-spectral mode, where the sentry's fire control system correlates received data from the different sensors to obtain a complete target profile. If the sentry is set to 'auto-remote', it will interrogate all targets in its sensor cone, using an Identification Friend Foe transponder. All UNSC and other AUR aligned personnel carry an IFF transponder in their communication gear which sends back a coded radio signal when interrogated. If the IFF return is positive, the weapon will let them pass, otherwise it will open fire. If the system is set to 'manual override' or 'semi-automatic', this information is flashed back to the command console, where the system operator can decide whether or not to fire. If the returned IFF is incorrect, it can act as a beacon for the turret.

The stabilized tripod automatically adjusts the boresight along the Y-Axis. The sentry gun's fire control computer limits the number of rounds expelled based upon the the target profile so that ammunition is conserved for longer operations.

UNSC Remarks

Individual and Crew Served Weaponry of the UNSCDF

Assault Rifles

MA6A Individual Combat Weapon System | M2A Carbine

Battle Rifle

M55C Enhanced Battle Rifle | M396 Designated Marksman Rifle

Machine Guns

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

Submachine Guns

M20A Submachine Gun | M12 Special Operations Carbine


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

Sniper Rifles

M113 Scout Rifle System | M1091 Sniper Rifle System | Sniper Rifle System 99G-S6 Anti-Materiel | Sniper Rifle System 99S-S6 Signature-Suppressed Anti-Materiel | Sniper Rifle System 40A-O Anti-Materiel/Anti-Vehicle | M99CA1 Special Application Scoped Rifle


M6L Personal Defence Weapon System | M57 Pistol

Energy Weapons

Weapon/Anti-Vehicle Model 6B Grindell/Galilean Nonlinear Rifle | MX4 Light Support Weapon | MX12 Directed Ion Energy Rifle | 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 | M556 Counter Defilade Grenade Launcher | M460C Automatic Grenade Launcher | M24 Underslung Grenade Launcher | M556 Counter Defilade 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

Angel Arm Specialties

Angel Arm Special 33 | Angel Arm Cutlass