SIGHT,BORE,MUZZLE
Item Name Code (INC): 21653
A sighting device consisting of (1) a string and a web belt which is attached to the outside of the muzzle end of the tube, or (2) a disk, with a central peephole, which is inserted in the bore, or (3) a short piece of tubing, with cross lines, which is inserted in the bore of a cannon.