Oddball Infobox-1-.png
Terminal.png This article, M20A Submachine Gun, was written by Ajax 013. Please do not edit this fiction without the writer's permission.
Production information

cR. 1484

Technical specifications
  • Length: 627 mm (474 mm stock closed)
  • Barrel: 210 mm
  • Weight: 1.3 kg (empty), 2.88 kg (loaded)
Fire Mode
  • Full automatic
  • Semi automatic
  • 3 round Burst
Ammunition Type

5x23mm caseless


Gas System With Rotating Breech

Rate of Fire

15 rnds/sec (900 rnds/min)


110 meters


200 meters


Necros War




The M20A Submachine Gun is a UNSC firearm. A short ranged weapon, it is usually seen in service with vehicle and weapon crews, as well as infantry equipped for boarding action and close quarters operations.


A successor to the M7/Caseless Sub-Machine Gun, it is largely unchanged in role, but has seen successive modifications to change its layout for improved performance. The biggest change to it has been a change in magazine position, moving it from the side mounting to a mounting along the upper receiver. This allows for better ambidextrous access to the magazine, allowing for easier handling.

The weapon itself has some changes in ergonomics, with a Misriah rail mounted over the magazine and on either side of the barrel. The weapon is lighter, with new polymers and lightened titanium alloys. This makes it more robust, especially in hostile environments. The weapon has other integrated features, like a large flash suppressor to improve it's close quarters performance. The barrel is threaded so the flash suppressor can be removed and replaced with another model, or a sound suppressor. It has fully adjustable and removable day/night iron sights.

The magazine utilizes a circular ramp where the magazine meets the breech. This rotates the horizontally stacked rounds in the magazine 90 degrees until they align with the horizontal breech. Once the first round is fired, the gases from previous rounds force the breech to rotate and chamber a new round. The magazine release button is located just above the grip, so it can be thumbed, allowing the operator to literally throw the magazine out. The cocking handle runs the length on the weapon and is on both sides, and must be pulled back to load should the breach be empty. There is no ejection port due to the nature of the rounds fired.


The M20 SMG is primarily used as a personal defence weapon. Small, compact and lightweight, it can be carried with ease, and an operator can carry large amounts of ammunition in a small space. As such, weapon teams, specialists, snipers and vehicle crew can carry it with ease, to support themselves in close quarters combat. Its also utilised by special forces, who utilise the small size to engage enemies at close quarters, the rounds capable of dropping lightly armoured targets with ease.


UNSC Remarks

"Nice to finally be able to do something with this thing besides just spout off bullets like water"

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

Community content is available under CC-BY-SA unless otherwise noted.