.45 Caliber

 is a Fallout 2 and a Fallout Tactics ammunition type.

Fallout 2
.45 bullets are a very nondescript and ineffective type of round, used only by the weak Tommy Gun and the heavy and short-ranged Grease Gun. Although they suffer no penalties, they also have no bonuses, like 7.62mm rounds. .45 weapons aren't horribly common either, with only Reno mobsters carrying Tommy Guns and Bishop's mercs with Grease Guns, so shops are about the only place you can find more. All in all, they'll be taking up trunk space while you guzzle down Microfusion Cells, 5mm JHP, and .223 FMJ.

Weapons using this ammunition

 * M3A1 "Grease Gun" SMG
 * Tommy Gun

Fallout Tactics
.45 rounds are decently rare ammunition, and are used in some of the more powerful handguns in the early stages of the game.

Weapons using this ammunition

 * Casull Revolver
 * Colt .45
 * Tommy Gun

Van Buren
Caius Drusus, one of Caesar's top Legionnaires, carried a .45 handgun, described as being "BIG". In addition, Frank LaFrancis, the ghoul at Burham Springs, carried a .45 submachine gun.

Amunicja .45