.22 Winchester Magnum Rimfire

.22 Winchester Magnum
.22 Winchester Magnum Rimfire
Type	Rifle
Place of origin	United States
Production history
Designed	1959
Manufacturer	Winchester
Produced	1959–present
Specifications
Parent case	.22 Winchester Rimfire
Case type	Rimmed, straight
Bullet diameter	.224 in (5.804 mm)
Land diameter	.219 in (5.6 mm)
Neck diameter	.2435 in (6.185 mm)
Base diameter	.2455 in (6.236 mm)
Rim diameter	.300 in (7.62 mm)
Rim thickness	.050 in (1.27 mm)
Case length	1.055 in (26.8 mm)
Overall length	1.350 in (34.3 mm)
Rifling twist	1-16"
Primer type	Rimfire
Maximum pressure	24,000 psi (170 MPa)
Ballistic performance
Bullet mass/type Velocity Energy 30 gr. (1.9 g) HP 2,300 ft/s (700 m/s) 322 ft⋅lbf (437 J) 40 gr. (2.6 g) JHP 1,875 ft/s (572 m/s) 324 ft⋅lbf (439 J) 50 gr. (3.2 g) JHP 1,530 ft/s (470 m/s) 300 ft⋅lbf (410 J)
Test barrel length: 24 inches (610 mm) Source(s): Cartridges of the World[1]

The .22 Winchester Magnum Rimfire, also known as the .22 WMR, .22 Magnum, .22 WMRF, .22 MRF,^[2] or .22 Mag, is a rimfire cartridge. Originally loaded with a bullet weight of 40 grains (2.6 g) delivering velocities in the 2,000 feet per second (610 m/s) range from a rifle barrel, .22 WMR is now loaded with bullet weights ranging from 50 grains (3.2 g) at 1,530 feet per second (470 m/s) to 30 grains (1.9 g) at 2,200 feet per second (670 m/s).^[3][4]