History
The .458 Winchester Magnum was designed for hunting dangerous game animals by emulating the performance of powerful English double rifle cartridges in a bolt-action rifle. The use of a bolt-action rifle offered hunters a cheaper alternative to the big-bore double rifle, and ammunition could be manufactured using available tooling. The .458 Winchester Magnum soon became a success as dangerous game hunters adopted the cartridge. Soon game wardens, wildlife managers, and professional hunters switched to the .458 Winchester Magnum as their duty rifle. The cartridge would become the standard African dangerous game cartridge in short order. By 1970 issues with the cartridge began to surface. Winchester had been using compressed loads of ball powder as a propellant for .458 Winchester Magnum. Due to clumping of the powder charge and the erratic burn characteristics associated with such loads, performance of the cartridge came into question. While Winchester addressed this issue, the stigma remained, and the cartridge's performance on dangerous game was suspect. However, the .458 Winchester Magnum remained the standard of measure for dangerous game cartridges. Recently, other .458 cartridges and various .416 cartridges have gained wider acceptance, but the 458 Win Mag remains one of the popular choices.Specifications
The .458 Winchester Magnum was designed from the outset to duplicate the performance level of the .450 Nitro Express and the .470 Nitro Express, which had become the mainstay of African dangerous game hunters. The .450 Nitro Express had been rated to launch a bullet at out of a barrel while the .470 Nitro Express would launch a bullet at out of a barrel. The design criteria for the .458 Winchester Magnum called for it to launch a bullet at out of a barrel. : :SAAMI compliant .458 Winchester Magnum cartridge schematic: All dimensions in inches illimeters The .458 Winchester Magnum's case was based on a .375 H&H case shortened to and renecked (to reduce taper) to accept a bullet. The cartridge remains the largest of the standard length magnum cartridge family released by Winchester, which includes the somewhat obsolete .264 Winchester Magnum and the popular .338 Winchester Magnum. SAAMI recommends a 6 groove with a twist ratio of 1:14 with a bore Ø of and a groove Ø of with each groove having an arc length of . While case volume varies between manufacturers, the typical Winchester case capacity is 95 grain of H2O (6.17 cm3). Maximum recommended pressure given by SAAMI is 53,000 c.u.p. while the CIP mandates a maximum pressure of .Performance
The original specifications for the cartridge called for a bullet to be fired at a velocity of through a barrel. Winchester achieved and surpassed this performance with their .458 Magnum cartridge. Current performance standards for the cartridge allow it to launch a bullet at a velocity of about through a barrel. The bullet is seen as the standard weight for a 45 caliber (11.43 mm) rifle bullet. This bullet has a sectional density of .341, which provides the bullet a high penetrative value at a given velocity. Among standard sporting cartridge bullets, the 45 caliber (11.43 mm) bullet has the highest sectional density. While bullets such as the 30 caliber (7.62 mm) bullet with a sectional density of .374 and even a 45 caliber (11.43 mm) with a sectional density of .409 exist these weights are not seen as a standard for those calibers. The .458 Winchester Magnum loaded with the solid bullet provides adequate penetration for dangerous game up to and including elephant. Due to the cartridge's relatively short case and powder column, longer bullets and those with a lower weight to length ratio—such as mono-metal bullets like the A-Square Monolithic Solid and the Barnes Banded Solids—may take up valuable powder space and lead to lower velocities and reduced performance. Hence, the reason for companies such as A-Square loading the .458 Winchester Magnum and even the .458 Lott with the Monolithic Solid instead of the , which is reserved for cartridges with large powder capacities such as the .450 Assegai and the .460 Weatherby Magnum. Bullets that tend to have a high weight to length ratios such as now discontinued Speer African Grand Slam solid tend to work better in the .458 Winchester Magnum. With modern powders the .458 Winchester Magnum is capable of launching a bullet at , a bullet at , a bullet at , and the bullet at . However, as no mainline ammunition manufacturer provides sub- .458 Winchester ammunition this is a choice for those who load their own ammunition or have access to custom-loaded ammunition.Sporting usage
The .458 Winchester Magnum was designed for use against heavy thick skinned African game species such as elephant, rhinoceros and African Cape buffalo. The exceptional sectional density of the bullet combined with a muzzle velocity of between provides the cartridge adequate penetration on these dangerous game species. Rifles produced for this cartridge usually weighed under . The combination of these factors helped the .458 Winchester Magnum become the most popular dangerous game cartridge on the African continent. Unlike the more powerful .460 Weatherby Magnum the .458 Winchester Magnum is not considered overly powerful for the larger felids such as lion or leopard in Africa. However, bullet selection is important for these felids as they are not considered thick skinned species with the largest of the lions weighing under . These species require bullets that open quickly upon impact, such as A-Square's Lion load. While the .458 Winchester Magnum is considered over powered for North American game species, the cartridge has found use for the hunting of large bears such as the polar and Alaskan brown bear and American bison. A few guides in Alaska and Canada carry rifles chambered in this cartridge to provide a defense against these largest bear species for themselves and their clients. The number one cartridge of professional guides in Alaska for Great Bears is the .338 Winchester Magnum. As almost all dangerous game hunting is conducted at short ranges with most shootings occurring well within a distance of , the .458 was not designed as a long range hunting cartridge. Its effective hunting range against large dangerous game is considered less than .Ammunition
Since the .458 Winchester Magnum was intended as a dangerous game hunting cartridge, almost all ammunition manufactured for the cartridge is manufactured for these game species. Bullets used to load the .458 Winchester Magnum by ammunition manufacturers generally range between . Winchester currently offers ammunition in the traditional Soft Point and the new Nosler Partition and Nosler Solid. The Winchester loading has a muzzle velocity of and muzzle energy of . Winchester's X4581 ammunition, which has a muzzle velocity of , is rated for CXP3 (large, non-dangerous) game species.Criticism
The .458 Winchester Magnum has had critics in its over 50 years of existence. By the late 1960s, professional hunters such asSee also
*References
{{DEFAULTSORT:458 Winchester Magnum Pistol and rifle cartridges Winchester Magnum rifle cartridges