This is a proprietary loading of the 6.5x54 Mannlicher
The .256 Magnum is a varmint and predator cartridge introduced by Winchester in 1960. In 1961 Ruger brought out the Hawkeye single shot pistol for the .256 Magnum. The next year (1962) Marlin chambered their Model 62 Levermatic rifle for the new Winchester cartridge....
Basically a 300 Win Mag necked to .257"
- info to follow -
This is the original story about the 257 Condor taken from GUNS MAGAZINE, Jan 1960 When a competent engineer decides to design a wildcat cartridge, some old ideas are given some new twists. The usual wildcatter reshapes an existing case, uses existing...
This is the 25 SOUPER (25-08) Improved, with a 40° shoulder.
The history of the HAWK range of cartridges can be found HERE
ICL = Increased Case Load. This is an improved version of the 257 Roberts
Smallest of 3 in a series developed by the Birmingham Small Arms Company. It was used in bolt-action rifles on the P-14 action.
Relatively new cartridge officially launched at the 2014 SHOT show. Full detail HERE
The 260 AAR, or All Around Rifle was originally designed by P.O. Ackley and is essentially a 257 Roberts Ackley Improved that was necked to 6.5mm.
The .260 was introduced in 1997 by Remington and has achieved a modest following. It is not nearly as successful as the 6,5 Creedmoor, despite being on par and in all probability a better cartridge. The reason maybe for not achieving a bigger following was the fact...
Long range match cartridge designed by Guido Wasser & Ivo Picek around 2000 from a 7.5 x 55 Swiss GP-11 case.
Les Baer Custom for an AR platform
This is the prototype for the 264 Win Mag, but without the belt
This round was also developed by Olin Corporation in July 1952 based on the .30 Light Rifle case necked to .27 cal. Specimen has a GM jacket with steel core.
Another version of the 284 Win case being necked down, this time to .270 cal.
Yet another attempt at a 1000 yd. match cartridge.
Designed by Elgin Gates and based on the 300 Savage case. It is one of the more popular of the IHMSA (International Handgun Metallic Silhouette Association) cartridges.
One of the Art Mashburn wildcats
Cartridge designed by Austrian engineer Franz E. Holler
The 270 Newton caliber is most probably not one of Charles Newtons inventions. It would seem that it came along much later than the original 30, 35, 40 and famous 256 (6.5-06) Newton calibers. This case is by Speer, but apparently Western also made it....
Basically a newer/different version of the 270-08 wildcat from the 1950's but with slight improvement. How slight is probably up for debate. The South African 270 SABI is almost identical to this.
Karlyn Flare Colonial Ammunition Co for the New Zealand Forestry Service The two S&B variations are proof loads SOUTH AFRICAN HEADSTAMPS AND VARIATIONS Red anodized aluminium dummy by THOR Engineering PMP basic brass...
Based on the 280 ROSS case that was shortened to 2.5" to form a match cartridge during the 1920's
This is the rimmed version of the 275 Holland & Holland developed round about 1911-12. Made for double rifles. ...
The 275 Hoffman is a normal 275 Holland & Holland with a proprietary headstamp.