.38 ACP

.38 ACP
Type	Pistol
Place of origin	United States
Production history
Designer	John Browning
Designed	1900
Manufacturer	Colt
Produced	1900–present
Variants	.38 Super
Specifications
Case type	Semi-rimmed, straight
Bullet diameter	.356 in (9.0 mm)
Land diameter	.346 in (8.8 mm)
Neck diameter	.384 in (9.8 mm)
Base diameter	.384 in (9.8 mm)
Rim diameter	.406 in (10.3 mm)
Rim thickness	.050 in (1.3 mm)
Case length	.900 in (22.9 mm)
Overall length	1.28 in (33 mm)
Primer type	Small pistol
Maximum pressure	26,500 psi (183 MPa)
Ballistic performance
Bullet mass/type Velocity Energy 115 gr (7 g) FMJ 1,150 ft/s (350 m/s) 338 ft⋅lbf (458 J) 125 gr (8 g) JHP 1,100 ft/s (340 m/s) 336 ft⋅lbf (456 J) 130 gr (8 g) FMJ 1,040 ft/s (320 m/s) 312 ft⋅lbf (423 J)
Source(s): Cartridges of the World[1]

The .38 ACP (Automatic Colt Pistol), also known as the .38 Auto, .38 Automatic, or 9×23mmSR, is a semi-rimmed pistol cartridge that was introduced at the turn of the 20th century for the John Browning-designed Colt M1900. It was first used in Colt's Model 1897 prototype, which he did not produce. The metric designation for the round is 9×23mm SR (semi-rimmed), which is not to be confused with other 9×23mm cartridges.