.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.

Fallout Tactics
Amunicja .45