"The Caestus Assault Ram is one of several types of assault rams used by the Imperium of Man. Assault rams are used for boarding actions during void battles and are capable of quickly placing boarding parties directly aboard enemy spacecraft. The Caestus Assault Ram is the common assault ram used by the Adeptus Astartes, due to the craft's high speed and phenomenal durability, which makes it highly prized by many Space Marine Chapters."

- from warhammer40k.wikia.com

This is going to be one of the many things that can be found inside the Battle Barge I am making. fully furnished, and also the middle gun can be operated via the cockpit!