Railgun

Railguns are the most commonly used weapons in the galaxy. They accelerate a projectile along conductive rails at a high velocity. With advances in technology railguns have become very compact, and even sidearms are railguns.

Railguns are also used on starships, which in space, are deadly, as the projectile will simply continue accelerating until it impacts a solid object. Kinetic screens will absorb such impacts, but they can only take so much before they collapse due to strain.

The power needed to operate a railgun is immense. Due to this, small arms generally have a battery built into the projectile magazine. And starships use excess energy from the ship's fusion plant to supplement its weapons' dedicated generators. This results in a massive buildup of heat, which causes problems when the ship is in combat and must have its radiator panels retracted.