The .256 Newton was a high-velocity, rimless centerfire cartridge based on the

.30-06 Springfield The .30-06 Springfield cartridge (pronounced "thirty- aught-six" ), 7.62×63mm in metric notation, and called the .30 Gov't '06 by Winchester, was introduced to the United States Army in 1906 and later standardized; it remained in military us ...

military cartridge and developed in 1913 by Charles Newton in conjunction with the

Western Cartridge Company The Western Cartridge Company was an American manufacturer of small arms and ammunition formerly based in East Alton, Illinois. Founded in 1898, it was the forerunner of the Olin Corporation, formed in 1944, of which Western was absorbed into. ...

. To make the .256 Newton cartridge, the .30-06 case was necked down to a caliber of .264 inches, the overall case length was shortened, body taper was increased, the neck was moved back, and the shoulder was given a sharper, 23-degree angle, as opposed to the 17-degree shoulder of the parent cartridge. The .256 Newton suffered from a lack of available slow-burning powders capable of fully exploiting the large capacity of the parent case. Newton's company went bankrupt after the end of

World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...

and production of commercially loaded ammunition ceased by 1938. After

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

, with a supply of 6.5mm rifles (.264 caliber), the availability of slower burning powders, and inexpensive, surplus .30-06 brass cases, shooters developed the 6.5mm-06 wildcat cartridge by necking down the .30-06 case to 6.5mm (.264 inches). In 1997, the

A-Square A-Square Company, LLC was a manufacturer of rifles, ammunition and bullets based in Chamberlain, South Dakota, in the United States. The company was one of 19 that are members of the SAAMI, Sporting Arms and Ammunition Manufacturer's Institution ( ...

company standardized the chambering as the 6.5-06 A-Square with the

Sporting Arms and Ammunition Manufacturers' Institute The Sporting Arms and Ammunition Manufacturers' Institute (SAAMI, pronounced "Sammy") is an association of American manufacturers of firearms, ammunition, and components. SAAMI is an accredited standards developer that publishes several Am ...

(SAAMI). Although substantially similar, the .256 Newton is not interchangeable with the .30-06 parent cartridge, the 6.5-06 wildcat chambering, or the SAAMI standardized 6.5-06 A-Square cartridge.

References

External links

Information from the Reloaders Nest

Newton rifle cartridges Pistol and rifle cartridges {{ammo-stub