- Caliber usually is measured
as the diameter of the bore
from land to opposite land
and expressed in hundredths
of an inch, thousandths of
an inch, or millimeters. However,
there is no standard set for
designating caliber. In some
cases, the caliber is given
as the diameter of the bullet,
which is the distance between
the grooves. For example,
a .270-caliber rifle bore
measures 270/1000ths of an
inch in diameter between the
lands and has a larger bore
diameter than a .223-caliber rifle.
- Caliber markings sometimes have a second number that has nothing to do with the diameter. For example, the popular .30-30 is a .30-caliber cartridge, but the second number is a term used from the days when the cartridge took 30 grains of powder. The "06" in .30-06 refers to the year (1906) it became the official ammunition of the U.S. military.
- Every rifle or handgun is
designed for a specific cartridge.
The ammunition must match
the data stamp on the firearm.
For example, there are several
.30-caliber firearms that
use the same bullet size but
are designed for different
cartridges (the .30-30, .30-06,
.308, and the .300 Savage).
If you cannot find the caliber
stamped on the firearm, take
it to a qualified gunsmith.
|
The
circles show bore sizes of
common cartridges. Having
the same bore size does not
mean different cartridges
are interchangeable. |
