The .500 A-Square is a belted, bottleneck rifle cartridge, developed by

Arthur Alphin Lieutenant Colonel Arthur Brent Alphin (born September 5, 1948) is a retired United States Army officer and military historian. He is the founder and owner of A-Square, manufacturer of American hunting rifles. He taught military history at Wes ...

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 The .50 BMG (.50 Browning Machine Gun), also known as 12.7×99mm NATO, and designated as the 50 Browning by the C.I.P., is a caliber cartridge developed for the M2 Browning heavy machine gun in the late 1910s, entering official service in 19 ...

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 Mozambique, officially the Republic of Mozambique, is a country located in Southeast Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west, and Eswatini and South Afr ...

." 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 The African buffalo (''Syncerus caffer)'' is a large sub-Saharan African bovine. The adult African buffalo's horns are its characteristic feature: they have fused bases, forming a continuous bone shield across the top of the head, referred to ...

as well as a backup 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/s (753 m/s) and muzzle energy of 8127 ft lbf (11019 J). In comparison: the parent cartridge, the .460 Weatherby Magnum as commercial loaded with a 500 gr (32.4 g) Monolithic Solid has a muzzle velocity of 2580 ft/s (786 m/s) and muzzle energy of 7389 ft lbf (10018 J). The .50 BMG as commercial loaded with a 661 gr (42.8 g) FMJ M33 ball ammo has a muzzle velocity of 2750 ft/s (838 m/s) and muzzle energy of 11102 ft lbf (15052 J). Although there is limited hand-loading information, bullet weights (hunting) are from between 300 gr (19.4) to 647 gr (41.9).

A-Square Company

In October 2011,

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 ( ...

ceased all ammunition operations.

References

{{DEFAULTSORT:500 A-Square Pistol and rifle cartridges Wildcat cartridges