<prompt> Calibre is defined as -Distance between two diametrically opposite groovesDistance between two diametrically opposite landsDistance between two diametrically opposite lands and groovesRatio of the length and width of the barrel  <response>: The synopsis of forensic medicine toxicology ; Dr k.s narayan reddy ; 28th edition ; Pg.no. 122 It is also called gauge . Also refer fig 8-16 cross section of a rifled barrel 