The 7mm STW (Shooting Times Westerner)
By Chuck Hawks
The 7mm STW has the honor of being (as far as I know) the first cartridge named for a gun magazine. STW stands for "Shooting Times Westerner," the same Shooting Times magazine to which many North American shooters subscribe or buy off the rack.
The 7mm STW was designed by Layne Simpson, Field Editor of Shooting Times, in 1979. In the May 1989 issue of Shooting Times an article about the cartridge by Mr. Simpson appeared, and the rest is history.
Federal, who seems to occupy the middle ground in 7mm STW factory loads, claims a MV of 3330 fps and muzzle energy of 3435 ft. lbs. with a 140 grain Trophy Bonded bullet (SD .248). The 200 yard figures are 2850 fps and 2520 ft. lbs. This is probably the best bullet weight for medium size big game animals.
The Federal factory load drives the 150 grain Trophy Bonded bullet (SD .266) at a MV of 3250 fps with ME of 3520 ft. lbs. The 200 yard numbers are 2770 fps and 2565 ft. lbs. This is a good all-around bullet weight for the 7mm STW, as it is for most 7mm Magnum cartridges.
For large game, Federal loads a 160 grain Sierra Spitzer Boat-Tail bullet at a MV of 3200 fps with ME of 3640 ft. lbs. The 200 yard figures are 2850 fps and 2890 ft. lbs. The trajectory of this sleek bullet (BC .563, SD .283) is as follows (Sierra figures): +2.96" at 100 yards, +3.61" at 200 yards, 0 at 300 yards, and -8.45" at 400 yards. The 7mm STW is an excellent long range big game cartridge with this weight bullet.
Handloaders can approximately equal all of these velocities, and in addition have at their disposal 120, 125, 130, and 175 grain bullets. The lighter bullets would seem to be pointless in a case as large as the 7mm STW, but the 175 grain bullet (SD .310) might be called upon for use on the largest game, when exceptional penetration is called for.
Here are some specifications of interest to reloaders: bullet diameter .284", maximum COL 3.600", maximum case length 2.850", trim to 2.840".
According to the fifth edition of the Nosler Reloading Guide the 160 grain spitzer bullets can be given a MV of 2950 fps with 69.0 grains of RL22 powder, and a MV of 3121 fps with a maximum load of 73.0 grains of RL22. The 160 grain bullet hits harder than the 175 grain bullet at all ranges out to 400 yards. Remington cases and Federal 215 primers were used for these loads, which were chronographed in a 26" barrel.
Note: A full length article about the 7mm STW can be found on the Rifle Cartridge Page.
Copyright 2004, 2013 by Chuck Hawks. All rights reserved.