Calibre of a firearm is?: (A) Distance between a land and groove, (B) Distance between two diagonally opposite lands, (C) Distance between two diagonally opposite grooves, (D) None
Answer is B. Distance between two diagonally opposite lands REF: Parikh 6th edition page 4.26 Caliber technicically means diameter of the inside of the bore (land to land) in 1/100' of an inch. Thus, caliber 22 means 22/100 inch= 0.22