M8 submachine gun

The M8 Submachine Gun was a compact personal weapon used by The Royal Allegiance during the Swarm War.

History
Traditionally, personal defence weapons and submachine guns sacrificed larger calibres, and therefore stopping power and penetration for smaller ammunition, which provided higher rates of fire and more carrying capacity. The M8 was developed to attempt to create a weapon, and an associated bullet size and type, capable of long ranges, being lightweight and most of all, maintaining power. In addition, it was required above all to be capable of piercing the natural exoskeleton of The Swarm, whilst still having a high rate of fire. The M8 was a marriage of these aims, resulting in a successful, rugged and versatile weapon. Introduced in 2753, the M8 was highly successful against the Swarm's armour and was highly used throughout the war.

Usage
The M8 SMG was used widely throughout Allegiance armed forces, due to its versatility and ease of use. It was used as a close quarters weapon for combat in urban areas and onboard ships, as a personal defense weapon or backup weapon for front line combat troops, and as the primary armament for troops not expected to see extended combat, for example vehicle crews and non-combat personnel. Often widely used by Allegiance Marines, it was widespread and well renowned as a dependable close and mid range weapon.

Design
The M8 Submachine Gun's design specifically focused on maximising range without a detrimental effect on the weapon's size or ergonomics. The weapon featured a bullpup layout, with the magazine located behind the trigger. This allowed for a longer barrel for the same weapon length, lending the M8 longer range than similarly sized SMGs. The M8 featured attachment rails along the upper and lower receiver, as well as on both sides, allowing for extensive customisation. The barrel featured a three way muzzle break which reduced the weapon's recoil while still allowing for suppressors and other attachments. Below the fire mode selector and safety catch was an ergonomically designed grip and trigger assembly, with a large oversized thumbhole. Underneath this and along the weapon's underside was the magazine well, where the standard 80 round magazine or 160 round helical magazine were loaded. On the underside of the weapon was the magazine release, which could not be accidentally pushed by dropping of the weapon. The weapon featured an integral, non retractable stock, like most bullpup weapons. The charging handle was located just below the top accessory rail, and the weapon was fully ambidextrous.

Ammunition
The M8 utilised advanced and powerful ammunition, a result of its need to overcome powerful organic and non-organic ceramic and composite armour. There were many ammunition types available in the M8's calibre, such as HVS/AP-HE, HPSDAP and HEPA rounds. The weapon's calibre was 4.5mm, which was a miniaturised round developed for use in SMGs and some pistols and personal defense weapons. It increased substantially the carrying capacity of the ammunition, and in some cases, for example submachine guns, its rate of fire. The associated decrease in mass and therefore power and penetration was combated by use of more advanced, and more expensive, ammunition types. The round was caseless, decreasing the mass and cost of the ammunition. instead of using the traditional method of a plasma-based synthetic block of propellant that combusted in the barrel to provide the bullet thrust, the M8 instead utilised a miniaturised Electrothermal Acceleration system. This gave the weapon an impressive muzzle velocity of 1,140m/s.

The system used a plasma discharge rather than a chemical reaction to force the bullet down the barrel. A high current, high voltage energy source was used along with a large capacitor bank, both of which were contained within the weapon and had a lifespan of 72 hours continuous usage. Both were attached in series to the electrode system in the M8's barrel. The capacitor was loaded with as high a voltage as possible,and the capacitor was then discharged. The gas in the gap between the electrodes would ionise, turning the non-flammable propellant into superheated conductive plasma. At this point, associated volumetric expansion would propel the projectile from the barrel at very high velocity. This added to the M8's already potent battlefield ability.

The ammunition could be loaded either using the standard, quadruple stacked, 80 round box magazine, which was the most commonly used method. Alternatively, a cyindrical 160 round helical magazine could be used, providing extended firing periods at the cost of a more bulky and heavier magazine. A favourite of troops going into combat was to load their weapon with the 160 round mag and then carry 80 round ones for when the former ran dry.

M8/S Submachine Gun
The M8/S, or shortened, was a smaller form of the standard M8 Submachine Gun. It featured substantially decreased range, due to its shortened barrel, though this made the weapon much more maneageable and light, especially useful in close quarters. While rarer throughout standard service, they were most popular with some special forces and marines involved in boarding actions, as well as pilots and vehicle crews. Unlike the standard M8, it was far less a standard issue battlefield weapon and far more a close range PDW. The weapon was basically the same, though featured a much shorter barrel and integral vertical foregrip, which acted as a handstop to prevent the user putting his hand in front of the weapon during operation. Other changes include rails located further back, rear of the fire mode selector, and a less protrusive external barrel. The weapon had an effective range of about 300m.