As used in this part, “.50 BMG cartridge” means a cartridge that is designed and intended to be fired from a center fire rifle and that meets all of the following criteria:
(a) It has an overall length of 5.54 inches from the base to the tip of the bullet.
(b) The bullet diameter for the cartridge is from .510 to, and including, .511 inch.
(c) The case base diameter for the cartridge is from .800 inch to, and including, .804 inch.
(d) The cartridge case length is 3.91 inches.