The 7mm Shooting Times Westerner (STW) was designed in 1979 by Layne Simpson as a wildcat cartridge and produced for the commercial market starting in 1989. The 7mm STW is based off the parent case 8mm Remington Magnum with a narrowed neck to fit a .284 inch bullet on a .315 inch neck. It has a large rifle magnum primer and a case length of 2.850 inches with overall length of 3.60 inches.
The ballistic performances based off five grain types for the 7mm STW on a 26 inch test barrel for muzzle velocity are 3,384 ft/s (120 gr), 3,268 ft/s (140 gr), 3,233 ft/s (150 gr), 3,177 ft/s (160 gr), and 3,047 ft/s (175 gr). The 7mm STW was first cartridge named for a gun magazine (Shooting Times Magazine) and Layne Simpson was the editor of STM at the time 1979.
Hand loading brass is available for the 7mm STW in a variety of loads. The muzzle velocity for performances are 3,200 ft/s (160 gr Spitzer w/69.0 grains of RL22 powder), and 3,121 ft/s (160 gr Spitzer w/73.0 grains of RL22 powder). The drop-off in trajectory and wound penetration occurs at approximately 335 yards distance. The 7mm STW is used by hunters for medium sized game and can also take down large sized game depending on the grain size bullet used.
