Overview
When it was introduced, the 300 WSM sported a new case that showed a lot of promise for uses in other calibers. In 2002 Winchester introduced new cartridges in its Winchester Short Magnum family, including the 7 mm WSM and 270 WSM. This new .270 cartridge was the third commercial .270 ever produced, and the first one in 60 years.
The 270 WSM is an improvement over the older 270 Winchester providing higher velocity with bullets of the same weight, and thus a flatter trajectory and more energy. Velocities tend to be about 250 ft/s (76 m/s) faster, in a cartridge that is shorter and can therefore be used in a shorter action for a more compact rifle if desired.
Read more about this topic: .270 Winchester Short Magnum