The M56 "Smartgun" is a 10mm general purpose automatic USCM squad support weapon effective to 1,500 meters. The pulse-action system employs a free floating recoil dampened motorized rotating breech mechanism chambered for the M250 series 10 mm x 28 caseless round. The gun also incorporates a muzzle booster to ensure the necessary operating forces from the large round. The cyclic rate is around 1200 rpm. The gun is constructed largely from molded carbon-fiber and light alloy stampings, though some interior parts of the mechanism are plastic. The replaceable barrel system is air cooled, though a heat sink attachment can be jacketed onto it. The system is mounted on an operator's harness and slaved to an infrared tracking system. The gun is self-steering on the mount, though firing can be commanded manually. The entire gun assembly (including harness and full ammo load) masses 17.82kg. The length of the gun itself is 122cm, and the length of the barrel is 54.5cm. Ammunition is stored in a drum mounted on the left side of the gun, it can hold 200 rounds.
Prepping the Smartgun
The M56A2 system consists of four major components: the operator's combat harness, the Head Mounted Sight (HMS), the articulation arm, and the gun itself. To prep the M56 for combat, operators must first don the combat harness. The harness is constructed from composite micromesh ballistic armour and is heavily padded to ease chafing at the shoulders and hips. The armoured breastplate holds the PRC 489/4 communications receiver/ transmitter and the tracking and targeting processor. Opening a backplate in the armour gives access to the processor, a sealed 'black box' line replacement unit (LRU) which can be easily unplugged and replaced in the field should it fail.
The stabilized articulation arm is attached to the left hip mounting point and plugged in via a coaxial cable to the processor and power outlets on the breastplate. The gun itself is clipped and secured to the end of the arm. The operator plugs the HMS into the tracking and comms system in the armour. The gun tracker is jacked into the processor by a universal connector and the gun itself must be powered up before the weapon is loaded. Power for the entire gun system is supplied by standard DV9 Lithium battery units, good for up to 50,000 rounds when fully charged. Both ends of the DV9 unit are plugged into the power leads which run from the articulation arm to the gun; common practice in the field is to let the battery hang free beneath the gun, where it is easily accessed in an emergency.
While the operator is standing, the gun is held and steered by its fore and aft grips. Operators have a wide degree of motion with the gun and can play it in an arc from their front to their left side, or point it directly upwards. When prone, operators must lie on their backs and employ the fore grip, while locking the cocking handle forward and using it as a side grip. The articulation arm is gyro-stabilised and provides additional recoil dampening to keep the gun steady while the operator is walking or running. When tracking a target, the arm will self-steer the gun barrel so as to boresight the target's centre of mass. An operator must be sensitive to these movements of the gun and allow it to aim itself, though they may override the gun's motion at any time simply by steering the barrel elsewhere.
When powered up, the gun begins tracking targets via its infrared tracker mounted above the barrel. The tracker consists of a 256 x 256 element platinum-silicide focal plane array cooled to 770 degrees K by a tiny cryogenic gas cooler working on the Stirling principle. This system monitors a 30 degree cone in front of the gun and transmits high-resolution thermal images in the 8-10 um range to a miniature video display in the operator's eyepiece. If a target is detected, the tracker will overlay a lighted box or rectangle on the screen over the target's centre of mass. The articulation arm will then self-steer the gun to aim at this point and as soon as it has done so, a target lock circle on the screen lights to indicate that the target is boresighted. If multiple targets or infrared false-target decoys appear in the sight, the operator simply steers the lighted box to bracket whichever target he wishes to engage.
Firing the Smartgun
All firing is controlled from either the forward hand grip or the rear firing handle; the operator fires the weapon by depressing the red 'fire' switch or pulling the firing handle upwards. A selector at the grip controls the gun's safety features and the rate of fire. There are three settings on this switch: Safe, Burst and Full Auto. Clicking off the Safety will automatically charge the weapon. (If there is a round already in the breech, the gun's diagnostic will prevent any further loading). The Burst setting will fire four round bursts, while the Full Auto feature will continue to fire the weapon at its full cyclic rate so long as the fire switch remains depressed.
The M250 10 mm x 28 ammunition is a 230 grain (14.9 gram) caseless projectile encased in a rectangle block of nitramine. Higher powered than the M309 round for the pulse rifle, the M250 also significantly differs in having a selectable fuse setting. A switch on the hand grip is used to select the ammunition fusing, which is set electronically as the round is loaded into the chamber. The 'Super' setting is optimised against soft targets and will detonate the round on impact, while the 'Delay' setting explodes the shell only after penetrating the target armour.
The M250 ammunition is stored on a roll of continuous plastic non-disintegrating link belt in the ammunition drum, which can be reloaded in the field. The gun motor drives the feed mechanism as well as the rotating breech and automatically loads each round off the belt and into the breech. In the event of a stoppage, the manual cocking handle at the right side of the weapon can be pulled to eject the round and clear the breech. This procedure can also be used to manually charge the mechanism.
M56 Armour & Combat Harness
This armour was constructed to bear the weight of the articulated arm of the Smartgun. The main armour component of this item is the large quick release titanium-aluminide plate which covers the wearer’s chest, this offers ballistic protection from all low powered small arms and fragmentation and has some success against heavier calibre weapons. The lower portion of the armour incorporates hip padding and an armoured plate for the hip & groin region made of micromesh ballistic material. No armour is afforded to the back area and most smartgun operators wear the armour in conjunction with an M2 Flak Vest. The other main function of the armour is to take the weight of the articulation arm of the Smartgun aswell as the Smartgun itself.. This attaches to the hip armour which has a mount to one side (dependent on the uses preference). The armour also incorporates 4 large wrap around padded straps over and under each arm and also a wrap around belt which the hip padding and abdomen armoured plate is attached to. The armoured breast plate also holds the PRC 489/4 communications receiver/ transmitter and the tracking and targeting processor for the smartgun.
M56 Head Mounted Sight
The head mounted sight incorporates many features of the M10 Ballistic Helmet, namely a tactical camera, microphone, IFF Transmitter and PRC 489/4. The only major difference being the inclusion of the M14 smartgun targeting eye piece, which has IR and low light capabilities (please see the Smartgun entry for details of how this functions). The headpiece draws its power from a pack located in the M5 armour. The headset prevents the use of an M10 Ballistic Helmet.
The M57 is the ‘sequel’ to the M56 smart gun used for the better part of the last two decades. Unlike the M56m the M57’s gun barrel does not autonomously track targets; instead the gun coordinates multiple guided projectiles. This increases fire rate significantly, reduces operator combat fatigue, and sidesteps lengthy training requirements. It also means that an M57 round can dynamically retarget mid-flight, should the firing M57 determine that the round’s initial target has already been defeated.
M57D ‘Dirty’ Smartgun
The M57D is an utterly vicious weapon that is sanctioned for extreme circumstances only. It fires rounds that shatter into hundreds of radioactive splinters inside their target, causing human survivors of the weapon to develop all manner of debilitating long-term health problems. It can create truly astounding radiation levels in larger targets, forcing these enemies to lose health for extended periods of time. Naturally, these upgraded Smartguns are plated with antiradiation armor as a safety measure for the user.
- During the battle in the Atmosphere Processor on LV-426, all Marines were ordered by Gorman to remove their Pulse Rifle magazines and Smart Gun batteries due to a risk of fracturing any cooling pipes. After they are confiscated by Sgt. Apone, Vasquez slyly passes Drake a spare battery she had hidden in her armor as well as another battery for herself, reactivating both guns.
- In the film, both Vasquez and Drake are equipped with Smart Guns. Vasquez's gun appears in the game Aliens: Colonial Marines and can be collected in the level "For Bella" near the Weyland-Yutani Facility and the Derelict.
- The M56 featured in Aliens was constructed by taking the MG-42 German machine gun modified with motorcycle parts and attaching it to a steadicam rig.
- The gun itself is over 50 inches long and due to the construction being primarily of metal, this created its own set of problems during filming due to its incredible weight. Its unwieldy nature required it to be physically attached to the actors using a “steadicam” filming rig. This allowed them to counter balance the gun using their own weight and leverage. Two were made for filming by Bapty & Co (The U.K.’s leading movie armourers) and was originally constructed as a live fire weapon which fired blank rounds during its on set usage. The markings on each read “adios” (on Vasquez' unit) and “bitch” (on Drake's).