Muzzle Loader's Interactive Gun Bore to Gauge Calculator for Flintlock and Percussion arms                                     enter barrel diameter in inches or millimeters for instant conversion and results


Bore diameter


Millimeters Inches
Entry may be in either millimeters or inches

Ball weight(pure lead)

Grams Ounces Grains







The Battle of Waterloo by William Sadler (c.1782 1839)

to printable bore gauge chart   other paintings by William Sadler visit british militaria forums
These calculations for flintlock and percussion arms are based on the ball diameter being equal to that of the bore. The result is the gauge which is the number of spheres of this diameter required make up a 1lb weight. A patched ball will be a little smaller and weigh less than the above figures suggest. The gauge however, remains as calculated.