Boltgun

The standard weapon of the Space Marines is the boltgun, also known as a "bolter". A bolter fires single-shot, four-round burst, or fully automatic fire.

Bolters are more effective and more complex than the standard pattern lasgun, but are also different as they are slugthrowers and so have incomparable operating conditions. Bolters are mainly used by the genetically engineered Space Marines due to the problems the heavy recoil and massive weight would pose for the Imperial Guard.

There are many variants of the bolter (referred to as Patterns); including the Ultima, Crusade, Heresy, Fillienostos, Nostra, Godwyn-Deaz, and Astartes Umbra patterns. Bolters are also highly customizable, and can be equipped with a wide variety of different modifications, such as optical scopes, bayonets, or even miniaturized versions of other weapons. These are referred to as Combi-Weapons (used mostly by the Kill-Teams of the Deathwatch). They can even be used as sniper weapons, especially when equipped with the Stalker silenced shells and the M40 Targeter system.