7mm Winchester Short Magnum

7 mm Winchester Short Magnum
WSM and WSSM family of cartridges. From left to right: .223 WSSM, .243 WSSM, .25 WSSM, .270 WSM, 7 mm WSM, .300 WSM, .325 WSM.
Type	Rifle
Place of origin	United States
Production history
Designer	Winchester
Designed	2001
Specifications
Parent cartridge	.404 Jeffery
Case type	rebated rim, bottleneck
Bullet diameter	0.284 in (7.2 mm)
Neck diameter	0.321 in (8.2 mm)
Shoulder diameter	0.538 in (13.7 mm)
Base diameter	0.555 in (14.1 mm)
Rim thickness	0.535 in (13.6 mm)
Case length	2.100 in (53.3 mm)
Rifling twist	1 turn in 9.5"
Primer type	large rifle magnum
Ballistic performance Bullet weight/type Velocity Energy 160 gr (10 g) 3,050 ft/s (930 m/s) 3,304 ft·lbf (4,480 J)
Source(s): Winchester

The 7mm Winchester Short Magnum (also known as the 7mm WSM) is a centrefire cartridge developed in partnership with Browning Arms Company and Winchester ammunition, making its debut and introduced to the shooting public in 2001.

Specifications

The 7mm WSM is similar to the .300 WSM and .270 WSM cases necked down to handle .284" bullets. However, the distance from the casehead to the datum line on the shoulder is longer for the 7WSM, preventing accidental chambering or firing of the .284" 7mm bullet in .270 WSM's .277" bore. Winchester claims a muzzle velocity (MV) of 3,225 ft/s with a 140 grain bullet for their 7mm WSM cartridge; the claimed muzzle energy (ME) is 3,233 ft. lbs. With a 160 grain bullet the Winchester figures are 2990 ft/s and 3176 ft. lbs. at the muzzle. The lighter, shorter 7mm bullets are preferred in these short case magnums.

Performance

The 7mm WSM cartridge achieves its useful purpose as an excellent cartridge for larger mule deer, sheep, black bear and elk.

References

• 7mm Cartridge Guide, 7mm WSM section