Small bore

Small-bore refers to calibers with a diameter of .32 inches or smaller. It may also refer to small-bore rifle competition. The medium-bore refers to calibers with a diameter between .33 inches up to .39 inches and large-bore refers to calibers with a diameter of .40 inches or larger. Miniature bore historically referred to calibers under .22. There is much variance in the use of the term small-bore which over the years has changed considerably with anything under .577 caliber considered small-bore prior to the mid-19th century.