The Hidden Hand
Boltguns are the standard firearm used by the Adeptus Astartes. They come in four varieties: Bolt Pistol, Bolter, Stormbolter, and Heavy Bolter (which is discussed in Heavy Weapons). Despite size and calibur differences all Boltguns function in the same manner. Storm Bolters are only available after selecting the Assault Master feat. The bolt (solid slug from which the weapons are named) is fired from the gas-powered weapon using a primary propellant which allows the bolt to clear the barrel, after which another form of primed charge is ignited essentually acting as a rocket propellant. This seconary charge allows the bolt to accelerate to an overwhelming speed. After the bolt has travelled a set distance, the slug arms, exploding on contact effectively shredding the target with a small fragmentation explosion. This allows bolters to carry the High Crit property as well as a unique exploding crit up to x2 on regular bolters, but some legendary bolters can multiply even higher!