 What the 6.5-08 provided over the .243 Winchester, .308 Winchester, and to a lesser degree the 7mm-08 Remington was bullets with excellent ballistic coefficients and sectional densities.Since the 6.5-08 was a wildcat cartridge, variations existed between cartridge chambers depending on the reamer used to cut the chamber.Furthermore, depending on whether one chose to form the case from .243 Winchester or .308 Winchester influenced the neck thickness and therefore the dimensions of the cartridge.