During the late 19th century and early 20th century, the U.S. Cavalry began trials to replace their sidearm arsenal of issued .45 Colt Single Action Army (SAA) in favor of the more modern and versatile double-action revolver in .45 Colt.

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The .45 ACP has 1.62 mL (25 g H2O) cartridge case capacity.
45 Auto maximum CIP cartridge dimensions. All sizes are

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The .45 ACP is an effective combat pistol cartridge. It combines accuracy as well as stopping power for use against human targets, has relatively low muzzle blast and flash, and it produces a

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Magazine capacity varies depending on the type of firearm. Standard (not extended) single-stack magazines, pistols based on the 1911 design

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Rounds are available from 68 grains to 300 grains (4.4 g to 19 g) with a common load being the standard military loading of a 230-grain (15 g) FMJ

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• 45 (colloquial in English and Spanish)
• .45 Rimless Smokeless
• .45 Auto

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Several US tactical police units still use the .45 pistol round. While high capacity firearms are available in .45 ACP, the greater length and diameter of the .45 ACP means that the grip of the pistol must be longer and wider than the grip of a comparable pistol of a

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