The diameter of the bullet that is fired, along with the dimensions of the cartridge that the gun will fire. For instance, the barrel may be the size for a bullet that is 32/100ths of an inch- but depending on the chamber dimension, that could be a .32 Auto, 32 S&W, or a 32-20. If the caliber is not known, then materials like Cerro-Safe are used to make a casting of the chamber, and the casting is measured with a micrometer.
Have it examined by a competent gunsmith
.357 mag in revolver .45 auto in semi auto
A 50 calibre machine gun can have any length or width. The inside of the barrel is 1/2 inch. Gradually calibre as a gun size is being dropped in favor of metric. For example 9 mm is replacing 38 calibre. A 38 calibre pistol will shoot a 9 mm bullet. Mortars are now 61 mm instead of a calibre.
a .45 caliber.
for a rifle it is thought to be a .50 calibre but a gun company made there own for there own sniper rifle the .408 calibre
$275 TO $350 DEPENDING ON CONDITION
His .50 calibre revolver was based on a Crosman 3357 .50 calibre paintball revolver.
A .50 calibre cartridge is measured as 12.7mm in metric terms, while a 7.62 projectile is in the .30 calibre range.
@890 mps
A big gun is a large artillery gun or one of the largest-calibre naval guns, or a person, group or thing which is powerful, influential, or effective.
A 50 caliber gun, or more properly, a .50 caliber gun is a firearm having an internal bore diameter of 1/2 or .50 of an inch.
It's not. It has its niche, and there are applications where another calibre would be more desirable.