Shotgun slug

The only legal way to obtain bullets over a .50 cal without paying extortion money to the goverment

A 12 guage Shotgun slug is .729 of an inch. Making it a 72 caliber bullet. Compare that to a bullet shot put of a desert eagle which is .500 of an inch.

A 10 guage slug diamater is 0.775, basically a 77 caliber bullet.

Shotguns that fire slugs are basically the biggest bore guns you can legally obtain without paying goverment extortion money.