7mm Shooting Times Westerner
| 7 mm STW | ||
|---|---|---|
| Type | Rifle | |
| Place of origin |  United States |
|
| Production history | ||
| Designer | Layne Simpson | |
| Designed | 1979 | |
| Produced | 1989-Present | |
| Specifications | ||
| Parent case | 8 mm Remington Magnum | |
| Case type | Belted, bottleneck | |
| Bullet diameter | .284 in (7.2 mm) | |
| Neck diameter | .315 in (8.0 mm) | |
| Shoulder diameter | .4868 in (12.36 mm) | |
| Base diameter | .5126 in (13.02 mm) | |
| Rim diameter | .532 in (13.5 mm) | |
| Rim thickness | .220 in (5.6 mm) | |
| Case length | 2.850 in (72.4 mm) | |
| Overall length | 3.60 in (91 mm) | |
| Rifling twist | 9 | |
| Primer type | Large rifle magnum | |
| Ballistic performance | ||
| Bullet weight/type | Velocity | Energy |
| 120 gr (7.8 g) X | 3,384 ft/s (1,031 m/s) | 3,052 ft·lbf (4,138 J) |
| 140 gr (9.1 g) X | 3,268 ft/s (996 m/s) | 3,321 ft·lbf (4,503 J) |
| 150 gr (9.7 g) BT | 3,233 ft/s (985 m/s) | 3,482 ft·lbf (4,721 J) |
| 160 gr (10 g) Partition | 3,177 ft/s (968 m/s) | 3,587 ft·lbf (4,863 J) |
| 175 gr (11.3 g) PSPCL | 3,047 ft/s (929 m/s) | 3,609 ft·lbf (4,893 J) |
| Test barrel length: 26" Source(s): Accurate Powder [1] |
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The 7mm Shooting Times Westerner, sometimes refereed 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.
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[edit] Background
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. All mass-market 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.
[edit] Performance
Dimensionally and ballistically, there are similarities between the 7mm STW and the 6mm cartridge based on the .375 H&H Magnum case necked down, known as the .244 H&H Magnum.[citation needed]
[edit] See also
- 7mm caliber for other cartridges of this caliber. The A Square Nosler 140 gr Partition allegedly has 2040 ft pounds of energy at 500 yards and 2080 ft pounds in its 160 gr. Nosler. A Square reports the highest energy out to 500 yards of any cartridge of similar weights. The 140 and 160 grain cartridges have very similar trajectories and this can be checked out in Tom Forkers Ammo 3 where A Square also has the least wind drift and best drop figures of all cartridges. The 160 gr. cartridge reportedly drifts only 53 inches with a ten mile and hour 90 degree crosswind at 1000 yds. and the 160 gr. caartridges and drops only 200 inches when zeroed at 200 yds. A Square recommends zeroing its cartridges at 300 yds. where the 140 gr merely drops 7.27 inches a 400 yds. and the 160 drops a mere 10 plus inches.
[edit] References
- ^ "7 mm STW data" from Accurate Powder
- ^ "The 7mm STW (Shooting Times Westerner)" by Chuck Hawks
- ^ "The 7mm STW (Shooting Times Westerner)" by Chuck Hawks (subscription only)
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