.260 Remington

The .260 Remington (also known as 6.5-08 A-Square) cartridge was introduced by Remington in 1997. Many wildcat cartridges based on the .308 Winchester case had existed for years before Remington standardized this round. Although loaded to higher pressures, the ballistics of this cartridge are basically similar to the 6.5×55mm when bullet weights do not exceed 140 grains. When loaded with heavier bullets, the 6.5×55mm is capable of greater velocity. Due to its shorter overall length the .260 Remington can be chambered in a shorter length bolt action than the 6.5mm Swedish.

Because 6.5 mm (.264") bullets have relatively high ballistic coefficients, the .260 Remington has seen success in rifle competition. It is capable of duplicating the trajectory of the .300 Winchester Magnum while generating significantly lower recoil. Also, converting a rifle chambered for the .308 Winchester (or any of its offspring, such as the .243 Winchester, 7mm-08 Remington or .338 Federal) to .260 Remington generally requires little more than a simple barrel change.

.500 A-Square

The .500 A-Square is a belted, bottleneck rifle cartridge, developed by Col. Arthur B. Alphin in 1976. The cartridge is based on the .460 Weatherby Magnum necked up to accept the .510 in (13.0 mm) bullet; the same as the .50 BMG cartridge. This was Col. Alphin's first commercial sporting cartridge and was designed in “response to some severe problems experienced with the .458 Winchester on safari in Mozambique.”

The .500 A-Square was a proprietary cartridge and the world's most powerful commercially available “sporting” cartridge. However, the .50 BMG is the world's most powerful commercial cartridge for any shooting purpose. The .500 A-Square is used specifically as an African, thick skin, dangerous game, rifle cartridge for the hunting of Elephants and Cape Buffalo as well as a back up gun for professional hunters and guides.

Overview

The .500 A-Square cartridge was commercially available from both A-Square and Midway USA as loaded ammunition. The ammunition comes in three loads: 600 grains (38.9 g) Monolithic Solid; 600 grains (38.9 g) soft nose thick jacket and 600 gr (38.9 g) soft nose thin jacket. All bullet/cartridge combination are advertised with a muzzle velocity of 2470 ft/sec (753 m/s) and muzzle energy of 8127 ft-lbf (11019 J).

6.5-06 A-Square

The 6.5-06 A-Square is a centerfire rifle cartridge that originated as a wildcat, based on the popular .30-06 Springfield. A-Square standardized the dimensions of the cartridge and submitted them to SAAMI in 1997.

Design

The 6.5-06 A-Square uses a .264" diameter bullet loaded into a modified .30-06 Springfield cartridge. The neck is reduced to accept the smaller bullet, the shoulder is longer than that of the parent cartridge, and it has a 17.5 degree shoulder angle leading to the neck of the case, where the bullet is seated.

Uses

The 6.5-06 A-Square has power similar to that of the .270 Winchester and .308 Winchester, making it suitable for hunting medium-sized game such as deer and black bear. It is also used in competitions such as F-Class and Benchrest formats.

Availability of ammunition

Currently (2011) none of the major commercial ammunition manufacturers offer factory loaded 6.5-06 A-Square ammunition. There are smaller companies that custom load the cartridge however, and hand-loading can be accomplished using the proper set of dies and using .25-06 Remington, .270 Winchester, or .30-06 Springfield brass and making the proper modifications to fit the 6.5-06 A-Square chamber. After firing, the brass from the original cartridge (.25-06 Remington, .270 Winchester, or .30-06 Springfield) will be fire-formed to the exact dimensions of the 6.5-06 A-Square chamber.