| .256 Newton | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Type | Hunting | |||||||||||
| Place of origin | United States | |||||||||||
| Production history | ||||||||||||
| Designer | Charles Newton | |||||||||||
| Designed | 1913 | |||||||||||
| Manufacturer | Western Cartridge Company | |||||||||||
| Specifications | ||||||||||||
| Parent case | .30-06 Springfield | |||||||||||
| Case type | Rimless | |||||||||||
| Bullet diameter | .264 in (6.7 mm) | |||||||||||
| Neck diameter | .291 in (7.4 mm) | |||||||||||
| Shoulder diameter | .418 in (10.6 mm) Shoulder angle: 18° | |||||||||||
| Base diameter | .471 in (12.0 mm) | |||||||||||
| Rim diameter | .473 in (12.0 mm) | |||||||||||
| Rim thickness | .049 in (1.2 mm) | |||||||||||
| Case length | 2.440 in (62.0 mm) | |||||||||||
| Overall length | 3.40 in (86 mm) | |||||||||||
| Rifling twist | 1 in 10 in (250 mm) | |||||||||||
| Primer type | large rifle | |||||||||||
| Ballistic performance | ||||||||||||
| ||||||||||||
| Source(s): Newton Arms Company Catalog. 14th edition, 1920. IN Barnes, Frank C. "Cartridges of the World" Digest Books Inc., 1972. | ||||||||||||
The .256 Newton was a high-velocity, rimless centerfire cartridge based on the .30-06 Springfield military cartridge and developed in 1913 by Charles Newton in conjunction with the Western Cartridge Company.[1] 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.[2]
The .256 Newton suffered from a lack of available slow-burning powders capable of fully exploiting the large capacity of the parent case.[2] Newton's company went bankrupt after the end of World War I and production of commercially loaded ammunition ceased by 1938.[2]
After World War II, 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).[2] In 1997, the A-Square company standardized the chambering as the 6.5-06 A-Square with the Sporting Arms and Ammunition Manufacturers' Institute (SAAMI).[2][3] 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.[2]
References
- ↑ Barnes, Frank, and Amber, John T. Cartridges of the World (DBI, 1972), p.76, ".256 Newton".
- 1 2 3 4 5 6 ".256 Newton and 6.5-06". Terminal Ballistics Research. Retrieved 22 March 2018.
- ↑ "SAAMI 6_5-06 A-Square" (PDF). Sporting Arms and Ammunition Manufacturers' Institute. SAAMI. Archived from the original (PDF) on 2018-03-22. Retrieved 22 March 2018.
External links