The Bolter is a large .75 calibre assault weapon. It has a much greater mass than most standard-issue Imperial weapons such as the Lasgun, although it is slightly shorter in length. Unlike most Imperial ranged infantry weapons, it lacks a stock, resulting in a grip much like a pistol’s or a submachine gun’s.
A blessed creation of the Adeptus Mechanicus, the Godwyn Pattern has served the Space Marines for millennia, its design based upon ancient STC technology from long before the birth of the Imperium. The Godwyn is not the only pattern of Boltgun used by the Adeptus Astartes though, and many of the Space Marine Chapters have their own variants, such as the “Angelus” Bolter used by the Blood Angels, or the “Fenris” Pattern boltgun used by the Space Wolves. However, the Godwyn Pattern remains the most common weapon of the Space Marines and fills the role of the sacred Bolter, as cited in the Codex Astartes as the primary weapon of a Battle-Brother.