3-inch gun

A 3-inch gun is a gun with a 3-inch bore. Examples include:


 * 3-inch M1902 field gun 1904, 1905
 * 3-inch M1903 - US gun
 * 3"/50 caliber gun - US dual purpose naval gun
 * QF 3 inch 20 cwt - British anti-aircraft gun
 * 3-inch Gun M1918 - US anti-aircraft gun
 * 3 inch Gun M5 - US anti-tank gun