7 mm STW
Type Rifle
Place of origin 22x20px United States
Production history
Designer Layne Simpson
Designed 1979
Produced 1989-Present
Parent case 8 mm Remington Magnum
Case type Belted, bottleneck
Bullet diameter .284 in (Bad rounding hereScript error mm)
Neck diameter .315 in (Bad rounding hereScript error mm)
Shoulder diameter .4868 in (Bad rounding hereScript error mm)
Base diameter .5126 in (Bad rounding hereScript error mm)
Rim diameter .532 in (Bad rounding hereScript error mm)
Rim thickness .220 in (Bad rounding hereScript error mm)
Case length 2.850 in (Bad rounding hereScript error mm)
Overall length 3.60 in (Bad rounding hereScript error mm)
Rifling twist 9
Primer type Large rifle magnum
Ballistic performance
Bullet weight/type Velocity Energy
120 gr (Bad rounding hereScript error g) X3,384 ft/s (Bad rounding hereScript error m/s)3,052 ft·lbf (Bad rounding hereScript error J)
140 gr (Bad rounding hereScript error g) X3,268 ft/s (Bad rounding hereScript error m/s)3,321 ft·lbf (Bad rounding hereScript error J)
150 gr (Bad rounding hereScript error g) BT3,233 ft/s (Bad rounding hereScript error m/s)3,482 ft·lbf (Bad rounding hereScript error J)
160 gr (Bad rounding hereScript error g) Partition3,177 ft/s (Bad rounding hereScript error m/s)3,587 ft·lbf (Bad rounding hereScript error J)
175 gr (Bad rounding hereScript error g) PSPCL3,047 ft/s (Bad rounding hereScript error m/s)3,609 ft·lbf (Bad rounding hereScript error J)
Test barrel length: 26"
Source(s): Accurate Powder [1]

The 7mm Shooting Times Westerner, sometimes referred to as the 7mm STW began as a wildcat rifle cartridge developed by Layne Simpson in 1979.[2] It is an 8 mm Remington Magnum case that has been "necked down" (narrowing the case opening) by 1 mm to accept 7 mm (.284 in) bullets. This cartridge is named after the magazine Shooting Times where Layne Simpson is a regular contributor.


The 7mm STW graduated to commercial status when it was officially recognized by SAAMI in 1996.[3] Remington Arms Company was one of the first large ammunition companies to produce this cartridge in 1997, with others like Federal Cartridge Company, A-Square, and Speer also carrying it. Many US riflemakers now offer a selection of production models chambered for the 7mm STW, which has established a reputation as a fine long-range elk and large game rifle.

See alsoEdit


  1. "7 mm STW data" from Accurate Powder
  2. "The 7mm STW (Shooting Times Westerner)" by Chuck Hawks
  3. "The 7mm STW (Shooting Times Westerner)" by Chuck Hawks (subscription only)

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