How big is a bullet from a shotgun?

Answer 1

The size of a pellet is denoted by a number; for bird shot, this goes from the smallest, 12 (1.2 mm, 0.05 in), to the second-largest, 2, and then BB (4.6 mm, 0.18 in). In the case of buckshot, the digits 4, 3, 2, 1, 00 ("single-aught"), 00 ("double-aught"), 000 ("triple-aught"), and 0000 serve as the beginning and ending points ("quadruple-aught").

Answer 2

A shot gun does not fire bullets, it fires shot (hence the name). And shot is made of small pellets roughly an eighth of an inch in diameter.