Accurately Measures Internal Shotgun Bore Diameter On 28 Thru 10 Gauge
One gauge set measures the inside bore diameter of all shotgun gauges, from the little 28 to the big 10 gauge (except .410 bore). Accurately reads bore and choke constriction, chamber diameter or forcing cone length. Even helps identify bent or damaged barrels on used guns. Just zero the indicator with the gauge-setting ring, then insert the gauge end into the barrel. The Dial indicator model reads down to one-thousandth of an inch, while the Digital model reads to ten-thousandths of an inch on the LED readout and adds instant inch to metric conversions.
Big Book Catalog, Issue:68, Page:512
New Product Supplement, Issue:641, Page:018
SPECS: Brass tool head; hardened steel measuring bearings;
3/16" (4.7mm) dia. aluminum shaft with ½" (12.7mm) dia.
phenolic resin cover. 16" (40cm) overall length, 13½" (34cm)
maximum measuring depth. Includes two gauge heads, one for 10,
12, and 16 gauge, one for 20 and 28 gauge plus setting rings for
each gauge and complete instructions.