What is 30 bore cal?

Answer 1

I suppose you mean: What is a 30 caliber bore? The bore of a Rifle is referred to as the caliber, which equates to the diameter of the bullet it fired. A gun that shoots a 9mm bullet would be a 9mm caliber or the bore size. Most guns originally made in US were measured in INCHES. Thus a 22 caliber rifle was a gun that shot a 0.22 inch diameter bore. Since the US Army began to change over to the metric system, it began making guns to the 9mm and 7.62mm sizes. Some bores can have alternate names. A new pistol bullet is the 0.40 INCH caliber designed by Smith&Wesson is also referred to as the 10mm caliber. The bore size of Shotguns are measured using Gauge. For example, shotguns are referred to as 12-Gauge or 20-Gauge. Gauge is an unusual measurement. The gauge equates to the number of lead balls that are made to the diameter of shotgun's bore and totals a weight of 1 pound. Thus, a 12-gauge shotgun has a diameter that of a ball that would weight 1/12 of a pound. That means the Larger the bore of the shotgun, the smaller the gage number. A 12-gauge shotgun is bigger bore than a 20-gauge shotgun.