.270 Winchester Short Magnum

270 Winchester Short Magnum
270 WSM cartridge
Type	Rifle
Place of origin	USA
Production history
Designer	Winchester
Designed	2002
Produced	2002–present
Specifications
Parent case	.300 WSM
Case type	Rimless, bottleneck
Bullet diameter	.277 in (7.0 mm)
Land diameter	.270 in (6.9 mm)
Neck diameter	.3140 in (7.98 mm)
Shoulder diameter	.5381 in (13.67 mm)
Base diameter	.5550 in (14.10 mm)
Rim diameter	.535 in (13.6 mm)
Rim thickness	.054 in (1.4 mm)
Case length	2.100 in (53.3 mm)
Overall length	2.860 in (72.6 mm)
Rifling twist	1-10"
Primer type	Large rifle magnum
Maximum pressure (SAAMI)	65,000 psi (450 MPa)
Maximum pressure (C.I.P.)	63,817 psi (440.00 MPa)
Ballistic performance
Bullet mass/type Velocity Energy 90 gr (6 g) JHP 3,700 ft/s (1,100 m/s) 2,737 ft⋅lbf (3,711 J) 130 gr (8 g) HP 3,295 ft/s (1,004 m/s) 3,135 ft⋅lbf (4,250 J) 140 gr (9 g) SP 3,250 ft/s (990 m/s) 3,284 ft⋅lbf (4,453 J) 150 gr (10 g) SPBT 3,136 ft/s (956 m/s) 3,276 ft⋅lbf (4,442 J)
Test barrel length: 24" Source(s): "Shooting Times" [1] / Accurate Powder [2]

The 270 Winchester Short Magnum or 270 WSM is a short magnum cartridge created by necking down the .300 Winchester Short Magnum and fitting it with a .277 caliber bullet. The correct name for the cartridge, as listed by the Sporting Arms and Ammunition Manufacturers' Institute (SAAMI), is 270 WSM, without a decimal point.^[3] It is a member of the Winchester Short Magnum family of cartridges.