.30-06 by Chris Punnett 

Caption

The .30-06 cartridge can be looked at as the result of several different developments that took place during the closing decades of the nineteenth century. These developments were: the change from blackpowder to smokeless powder; the general acceptance throughout the world of the benefits of smaller caliber weapons; and the desire to move away from a rimmed cartridge. The move to smokeless powder and smaller diameter bullets had been accomplished to some degree with the adoption of the rimmed .30 Krag in 1892 but this proved to have a limited powder capacity. By 1901, work had started on a rimless cartridge which was based on an earlier rimmed experimental .30 caliber round. The result of this work was the .30 Ball Model of 1901 - the ".30-01" or "Thick-rim".
As its name implies, the rim on this cartridge was thick in comparison to more modern rimless cartridges including the .30-03 and .30-06 which followed. The bottle-necked case held a 220-grain round-nosed cupronickel-jacketed bullet.