View Full Version : gauges/calibers

tony stark
April 4, 2006, 01:06 AM
why is the .410 caliber shotgun measured in caliber instead of gauge, like every other shot gun. i know it would be about a 68 gauge, so why don't they call it a 68 gauge?

April 4, 2006, 06:19 AM
To my understanding they do measure it in gauge......


April 4, 2006, 09:54 AM
It is fairly confusing. I belive .410 is a bore (http://www.answers.com/main/ntquery;jsessionid=13s34s4oe772h?method=4&dsid=2222&dekey=.410+bore&curtab=2222_1&sbid=lc05b) that is measured using the caliber method. I know, did not answer your question.
The next most popular size is the .410, which is not a gauge per se, but a caliber.
The Gauge or bore (http://www.answers.com/topic/gauge-bore-diameter) (especially in British English) of a Shotgun is the diameter (caliber) of the barrel.

Calculating gauge

The gauge, or bore, is determined by the number of solid spheres of a diameter equal to the inside diameter of the barrel that could be made from a pound of lead. The term related to the measurement of black powder cannon, which were also measured by the weight of their round iron shot; a 6 pounder, for example, would fire a 6 pound (2.7 kg) spherical cast iron ball, which gave a bore diameter of about 3.6 inches (9.1 cm).
Shotgun Bore Diameter (http://www.globalsecurity.org/military/systems/munitions/12.htm)
10-Gauge = Bore Diameter of .775 inches
12-Gauge = Bore Diameter of .729 inches
16-Gauge = Bore Diameter of .662 inches
20-Gauge = Bore Diameter of .615 inches
28-Gauge = Bore Diameter of .550 inches
67-Gauge = Bore Diameter of .410 inches

Shotgun Chamber Length
10-Gauge = Chamber Length of 2.875 inches - 3.500 inches
12-Gauge = Chamber Length of 2.750 inches - 3.500 inches
16-Gauge = Chamber Length of 2.750 inches
20-Gauge = Chamber Length of 2.750 inches - 3.000 inches
28-Gauge = Chamber Length of 2.875 inches
67-Gauge/.410 = Chamber Length of 3.000 inches

April 4, 2006, 10:01 AM
Why do you look for logic in shotguns ??? Bore/ gage, dram equivalent, release triggers, rifled/smoothbore !!!:confused:

April 4, 2006, 10:17 AM
It was set this way before you were born and has stuck. There is no other reason.

April 4, 2006, 08:45 PM
Actually the 410 is not referred to as a gauge because it is in fact an exact measurement of the bore, unlike the other gauges. The others follow the age old description of the bore diameter and the lead balls thus for example, the twelve bore is so called because it takes twelve balls of the gauge's diameter to equal one pound; the sixteen gauge requires sixteen lead balls equalling one pound and so on.This seems to be the rule of thumb uesd by old time gunsmiths and it has stuck ever since.
The .410 bore is just that - .410 of an inch. Having said that however, European and some other non American manufacturers do sometimes refer to the 410 bore as the 36 gauge.

April 4, 2006, 09:25 PM
There is a reason the .410 and the 45 Colt are interchangable in some guns. The .410 is the off shoot of a survival cartridge designed for the Calvary for out west back in the 1800's. And in all reality the goverment and some of the cartridge and gun makers back then made absoutely no sense in how they named there cartridges! :rolleyes: