Bore Size Table
Gauge | Bore Diameter or Calibre |
1 | 1.669" |
2 | 1.325" |
3 | 1.157" |
4 | 1.052" |
5 | .976" |
6 | .919" |
7 | .873" |
8 | .835" |
9 | .802" |
10 | .775" |
11 | .751" |
12 | .729" |
13 | .700" |
14 | .693" |
15 | .677" |
16 | .662" |
17 | .650" |
18 | .637" |
19 | .626" |
20 | .615" |
21 | .605" |
22 | .596" |
23 | .587" |
24 | .579" |
25 | .571" |
26 | .563" |
27 | .556" |
28 | .550" |
29 | .543" |
30 | .537" |
31 | .531" |
32 | .526" |
.410 | .410" |
Gauge - System of measurement for the internal bore diameter of a smooth-bore firearm based on the diameter of each of that number of spherical lead balls whose total weight is one pound. The internal diameter of a 12 gauge shotgun barrel is therefore equal to the diameter of a lead ball weighing 1/12 pound, which happens to be .729" (Or in British: Bore.)
.410 is not really a gauge, except by convention. It is the actual diameter of the bore in decimal inches.
The Gauge/Bore system is also used to describe the internal barrel diameter of large-bore, 19th century, English, single-shot and double-barrel black powder rifles.
The Hallowell & Co. Illustrated Firearms Dictionary is for informational purposes only. We do not necessarily offer the items described above for sale. Please click on any of the links below to see what we actually do have available for purchase.
American Shotguns English Shotguns European Shotguns Double Rifles Magazine Rifles Single Shot Rifles Combination Guns
Winchester Colt Smith & Wesson Other Handguns Antique Guns New Arrivals Custom Knives Other Neat Stuff
Who We Are How to Order We want to buy your Gun(s) Recommended Links Historical Gallery
Firearms Definitions, Abbreviations & Opinions Store Photos Magazine Articles Home
Hallowell & Co., Inc. PO Box 1445. Livingston, Montana 59047 USA Tel: 406 222-4770 Fax: 406 222-4792 Email: morris@hallowellco.com
Hours: Tuesday - Saturday, 10 - 6. (Mountain Time) Our inventory is constantly changing. Please bookmark this site and return often.