The Armadyne ECR
The Armadyne ECR is an impressive looking weapon, with a blocky profile, fully shrouded barrel, and hardpoints for connecting a variety of tools and gadgets. The default automatic coil gun, the ECR has been a figurehead in Armadyne's arsenal for decades.
The ECR is a simple weapon, following the standard rifle configuration used by automatic weapons for centuries. The power pack is built into the stock, and where the bolt/receiver is in a normal rifle, the magazine loads into a accelerator chamber. The magazine itself holds 200 rounds of 2x40 solid shot. These nail shaped projectiles are light, but once accelerated to 800 m/s they are more than sufficient for punching holes in human beings, light vehicles, and other unarmored targets.
The ECR has a number of nicknames, with the most common being the Nail gun. Is is also known as the automatic stapler, pinshooter, and buzzgun for its high rate of fire.
Armadyne has been manufacturing the ECR for decades, having reverse engineered the design from a handful of centuries old prototype coil guns manufacturing during the closing days of the Resource Wars. Rather than falling into any of the best categories, the ECR was reliable, and its stopping power, range, and accuracy were comparable favorably to quality conventional firearms. Other magnetic weapons have come out with much higher muzzle velocities, greater stopping power, longer range, greater accuracy, but with these 'best' positions they have inherent flaws. While the ECR doesn't dominate in any given field, it is a very good all round gun.
The hard point system allows for the gun to be mounted with a SmartGun system, laser range finder, hyperedge bayonet, etc. This makes it popular with field units. The power pack is modular as well, making it a robust and easy to use weapon. There are variant ECRs that have a rail to mount a smaller weapon under the main barrel, with magnetic grenade launchers being the most common.
The biggest flaw of the ECR is the limited penetration potential. When facing power armor soldiers, androids, or armored vehicles, the ECR 'nails' shatter or flatten against the armor. More than one squad of infantry, emboldened by the reliability and power of their rifles have been destroyed after encountering heavy infantry and finding their weapons more a nuisance.
The ECR is a common weapon in second world military arsenals, as well as in the rank and file of security companies. Mercenaries favor the weapon for its intimidation factor, and it has since become more associated with mercenaries and contractors than actual military forces.
Author's Note: The ECR was spawned from the visual appeal of Tom Cruise's rifle in the 2013 movie Oblivion and from a futuristic zombie apocalypse game I am running with my wife. She has found the ECR a valuable weapon for mowing down zombies, and its rechargeable power pack and high ammo capacity have saved her more than once.