The .303 Savage was that company's attempt to capture a share of the market that the .30-30 Winchester cartridge would come to dominate. Savage developed their .303 as a (unsuccessful) military cartridge in 1895. It became a commercial success in their Model 1899 lever action rifle, and remained moderately popular into the 1930's. Despite its ".303" nomenclature, the .303 Savage is usually reloaded with standard .308" (.30 caliber) bullets. The .303 Savage case is a rimmed, bottleneck type with a rim diameter of .505", a base diameter of .442", a shoulder angle of 16 degrees, and a length of 2.015". In a practical sense, it has about 1-2 grains greater useful capacity with common powders than the .30-30 case. Like the .30-30, the .303 has always been loaded with flat point or round nose bullets, even though the Savage Model 99 rifle used a rotary magazine which could (and did in other calibers) accommodate spitzer bullets. 

This text is based on information from “Cartridges of the World”, Hodgdon reloading manual, the cartridge designer and/or own resources.