Small-bore refers to calibers with a diameter of .32 in (8.1 mm) or smaller.1 It may also refer to small-bore rifle competition. The medium-bore refers to calibers with a diameter between .33 in (8.4 mm) up to .39 in (9.9 mm) and large-bore refers to calibers with a diameter of .40 in (10 mm) or larger.2 Miniature bore refers historically to calibers of .22 in (5.6 mm) or smaller.
There is much variance in the use of the term small-bore, which over the years has changed considerably with anything under .577 in (14.7 mm) caliber considered small-bore prior to the mid-19th century.3
Small-bore competition
Small-bore competition often refers to shooting competitions conducted with .22 Rimfire target rifles.45
References
References
- "Medium Bore Musings".
- "Big Bore Rifle Cartridges".
- "Historic small-bore Enfield rifles, training rifles and BSA rifles; plus league competitions".
- "SmallBoreRifle - What is Smallbore Rifle Shooting?".
- http://compete.nra.org/documents/pdf/compete/RuleBooks/SBR/sbr-book.pdf Small-bore rifle NRA rule book
- Historic small-bore Enfield, BSA and other Service, Training and Target rifles reference pages, with league competitions for such rifles [1]