The Godwyn pattern Bolter has a magazine of 28. All well and good. On page 28, Sergeant Kell of the Dark Angels shows how silly he can be by stating:
“This is the holy bolter. It is a Godwyn-pattern model with an ammo
counter, sinister/dexter locking mechanism, and a sickle magazine
containing 30 rounds. Each round is a .75 calibre bolt with a
diamantine tip, depleted deuterium core and mass-reactive detonator.
It fires in four-round bursts.”