Unprimed 7 mm STW cases are available from Nosler and Remington. The case is also easily formed as I did years ago by using a 7 mm STW full-length resizing die to neck down 8 mm Rem. Mag. brass. Necking down .300 H&H Mag. brass and fireforming with a reduced propellant charge is another option; neck length ends up a bit shorter than standard but not enough to really matter. Heavy charges of slow-burning powders required for top velocities call for a magnum primer. The Rem. 91/2M and CCI 250 are good choices but the Federal 215 in either its standard or Gold Medal Match variation is the most popular.

There was a time when I used 140-grain bullets at 3,400 fps or so almost exclusively when hunting deer-size game in open country. I still do on occasion, but nowadays I am more inclined to stick with a good 160-grain bullet on everything I hunt with the 7 mm STW. When exiting the muzzle at 3,200 fps and zeroed 3-inches high at 100 yards, a bullet with a ballistic coefficient in the neighborhood of .500 is dead on point of aim at 300 yards and only about 8-inches low at 400 yards, which is about as far away as I care to shoot at game with any cartridge. Residual energy at that distance is around 2,300 ft.-lbs.

I recommend a barrel no shorter than 24 inches for the 7 mm STW and actually prefer 26 inches. Even longer doesn’t hurt. A friend of mine who has a custom rifle on the Ruger No. 1 action in 7 mm STW with a 30-inch barrel gets velocities about 130 fps faster than I get from my 26-inch barrels. Overall length of his Ruger No. 1 with a 30-inch barrel is the same as a long-action Model 700 with a 26-inch barrel.

There has been a bit of confusion over how the 7 mm STW case was originally formed. As clearly illustrated in SAAMI drawings for the two cartridges, the body of the 7 mm STW case tapers to a maximum diameter of 0.487 inches at its juncture with the shoulder, the same as for the 8 mm Rem. Mag. case. This is also evident in cartridge drawings shown in various reloading manuals. While I am on the subject, the .257 STW and 6.5 STW cases were also formed by necking down 8 mm Rem Mag. brass with no other change. Today they are more commonly formed by necking down 7 mm STW brass.

The .358 STA is the one exception in the family. When developing it, I chose to increase the capacity of the 8 mm Rem. Mag. case by fire-forming it to less body taper and a sharper shoulder angle. As shown in the SAAMI drawing for it, diameter at the body/shoulder juncture is 0.502 inches and shoulder angle is 35 degrees. Those same dimensions along with .358 STA load data also appear in the 6th and 7th editions of the Nosler Reloading Guide.