The Collaborative International Dictionary
Rimbase \Rim"base`\, n. (Mil.) A short cylinder connecting a trunnion with the body of a cannon. See Illust. of Cannon.
Wiktionary
n. (context military historical English) A short cylinder connecting a trunnion with the body of a cannon.
Usage examples of "rimbase".
The rifled cannon in service have the breech-sight on the side of the breech and the front sight on the rimbase, which permits the gun to be accurately aimed and the object kept in view at all elevations.
Furthermore, with the sight on the right rimbase, it is not convenient for the 2d Captain to attend the screw without interfering with the aim.
The rod being held parallel to the axis of the bore, with the side of the head pressing the rimbase, the knife-edge will be in a proper position to fall into the base line when moved to find it.