The parent cartridge of the 270 Winchester and the 30-06 Springfield is the 30-03. The case length for the 270 and the 30-03 is 2.54". The 30-06 was created by shortening the case length to 2.484 and dropping bullet weight from 220 grains down to 150 grains and raising the velocity from 2,300 fps to 2,700 fps.
