| 7mm Shooting Times Westerner | |
| Origin: | United States |
| Type: | Rifle |
| Designer: | Layne Simpson |
| Design Date: | 1979 |
| Production Date: | 1989-Present |
| Parent: | 8mm Remington Magnum |
| Case Type: | Belted, bottleneck |
| Bullet: | .284 |
| Neck: | .315 |
| Shoulder: | .4868 |
| Base: | .5126 |
| Rim Dia: | .532 |
| Rim Thick: | .220 |
| Case Length: | 2.850 |
| Length: | 3.60 |
| Case Capacity: | 93.3 gr of H2O |
| Rifling: | 1 in 9 in (229 mm) |
| Primer: | Large rifle magnum |
| Max Pressure: | 65000 |
| Pressure Method: | SAAMI[1] |
| Bw1: | 120 |
| Btype1: | X |
| Vel1: | 3384 |
| En1: | 3052 |
| Bw2: | 140 |
| Btype2: | X |
| Vel2: | 3268 |
| En2: | 3321 |
| Bw3: | 150 |
| Btype3: | BT |
| Vel3: | 3233 |
| En3: | 3482 |
| Bw4: | 160 |
| Btype4: | Partition |
| Vel4: | 3177 |
| En4: | 3587 |
| Bw5: | 175 |
| Btype5: | PSPCL |
| Vel5: | 3047 |
| En5: | 3609 |
| Test Barrel Length: | 26" |
| Balsrc: | Accurate Powder [2] |
The 7mm Shooting Times Westerner, sometimes referred to as the 7mm STW, began as a wildcat rifle cartridge developed by Layne Simpson, Field Editor of Shooting Times, in 1979.[3] It is an 8mm Remington Magnum case that has been "necked down" (narrowing the case opening) by 1 mm to accept 7 mm (.284 in) bullets.[4]
The first major company to produce the 7mm STW was A-Square in 1994.[5] The 7mm STW graduated to commercial status when it was officially recognized by SAAMI in 1996.,[6] and the Remington Arms Company started to produce it in 1997,[7] with other ammunition manufacturers following. As of 2019, Federal Premium Ammunition is the only major manufacturer to still offer it on a regular basis, but smaller manufacturers also provide loaded ammunition.[8]