Accurately Measures Internal Shotgun Bore Diameter
Don't guess or estimate the internal bore diameter when you can know the exact measurement down to one-thousandth of an inch. Inexpensive, accurate, precision micrometer makes accurate measurements of bore, choke constriction, or forcing cone length. Plus, it will easily show bent or damaged barrels on used guns. Very easy to use: zero the micrometer with the gauge-setting ring, then insert the gauge end into the barrel. The micrometer will read the exact inside diameter in thousandths of an inch.
Big Book Catalog, Issue:65, Page:487
New Product Supplement, Issue:581, Page:012
SPECS: Brass tool head, hardened steel measuring bearings, aluminum micrometer housing, phenolic resin external shaft cover. 16" (40cm) overall length. 13-½" (34cm) maximum measuring depth. Includes 1 gauge setting ring for each gauge listed and complete instructions.