Description: proprietary cartridge for the Newton Arms Company introduced by the Western Cartridge Co. in 1913, it is based on a necked-down .30-06 cartridge case. While the 6.5 mm was a deservedly popular bore size for both military and hunting rifles in Europe, the .256 Newton holds the distinction of being the only American true 6.5 mm to be manufactured until 1958. While a very satisfactory hunting cartridge, it held no advantage over various .25 and .27 cartridges, for which a dide range of bullet designs was available, so did not prosper. A rare cartridge. Charles Newton was also connected with cartridge development for the Savage Arms Co.