.450 Rigby
Encyclopedia
The .450 Rigby Magnum Rimless better known simply as the .450 Rigby is a .45 caliber (11.6 mm) rimless, bottlenecked cartridge
intended for the hunting of heavy dangerous game. The cartridge is based on the .416 Rigby
necked up
to accept a 0.458 inches (1.2 cm) bullet. The cartridge is intended for use in magazine rifles. The cartridge should not be confused with the .450 Rigby Nitro Express which is a rimmed cartridge intended for double rifles.
) was on an elephant hunt in the Zambezi Valley. Both he and his professional hunter, Joseph Wright, were armed with .416 Rigby rifles for the occasion. An elephant was located and then shot in the lungs, but due to a misjudgment in distance several more rounds were required to finally bring down the elephant.
After this experience, Paul Roberts felt that a cartridge with a greater bullet weight of a larger caliber would have been more effective in that situation. Once Paul Roberts returned to the United Kingdom he necked up the .416 Rigby case to .458 caliber. The new cartridge fired the 480 gr of the .450 Nitro Express cartridge at a velocity of 2378 ft/s (724.8 m/s) from a 25.5 inches (64.8 cm) barrel. The new cartridge was named the .450 Rigby Magnum Rimless in 1994. The cartridge was put into production in 1995. The John Rigby & Company was building the .416 Rigby rifles on the 98 Magnum Mauser action. Since the .416 Rigby and the .450 Rigby use basically the same case, building rifles for the .450 Rigby was rather simple requiring only a chamber with a modification made in the collar area and a .458 caliber (11.43 mm) barrel.
The .450 Rigby dimensions and specifications are standardized and governed by the CIP.
The CIP recommends a bore diameter of 11.43 millimetre (0.45 in) and a groove diameter of 11.63 millimetre (0.457874015748032 in). Barrel will have a 6 grove rifling contour with a twist rate of one revolution in 420 mm (16.5 in) and a groove width of 3.6 millimetre (0.141732283464567 in). CIP specifies a maximum pressure of 4000 bar (58,015.1 psi).
or the .460 Weatherby Magnum
, the .450 Rigby was designed to operate at more moderate pressures. Maximum pressure limits enforced by CIP is given at 4000 bar (58,015.1 psi). At these pressures, the cartridge easily reaches the intended 2300–2400 ft/s (701–731.5 m/s) with the 500 gr bullet. The lower pressures provide greater operational reliability in tropical environments where the cartridge is intended for use. Heat can cause higher than normal pressures which can lead to difficulty in extracting the spent case. In a dangerous game hunting situation such failures can result in injury or possibly a fatality.
Unlike the .458 Winchester Magnum and to a degree the .458 Lott, the .450 Rigby reaches the coveted 2400 ft/s (731.5 m/s) velocity mark with the 500 gr with ease and well under the pressure limits imposed by the CIP upon the cartridge. Handloaders can take advantage of the wide range of .458 caliber (11.6 mm) bullets available. Acceptable bullets weight range from 300 gr to 600 gr. The 500 gr bullet can easily reach 2500 ft/s (762 m/s) and staying within the pressure limitation imposed on the cartridge.
Among commercial sporting cartridges, only the .460 Weatherby Magnum
offers a superior performance over the .450 Rigby. However, most bullets manufactured such as those by Hornady and Woodleigh are rated for .450 Rigby velocities rather than those achievable through the .460 Weatherby. For this reason actual performance and penetration and heavy thick skinned game species are on par between these two cartridges. The Weatherby cartridge has a 6% greater capacity than the .450 Rigby but operates at higher pressures.
For lighter game species and other non-dangerous plains game bullets weighing as little as 250 gr are available for handloading. The lightest of these bullets are manufactured for cartridges such as the .450 Bushmaster
or the .45-70 Government and the .450 Marlin
; these bullets may not be best suited for use with the .450 Rigby. Loaded correctly, the .450 Rigby will hit harder and shoot flatter than most big bore cartridge making a good plains game rifle, albeit more powerful a cartridge than necessary for plains game. While the .450 Rigby is too powerful for use against North American game, it is conceivable that the cartridge would provide a powerful stopper against polar and Alaskan brown bear and is equally suited for the harvesting of the American bison.
The .450 Dakota launches a 500 gr at 2550 ft/s (777.2 m/s), a 550 gr at 2450 ft/s (746.8 m/s) and the 600 gr at 2350 ft/s (716.3 m/s). While these velocity values are greater than that of the .450 Rigby cartridge, the Dakota ammunition is loaded to near maximum pressure levels while the .450 Rigby is loaded to a pressure level far below the 4000 bar (58,015.1 psi) stipulated by the CIP. Given equal pressure level the .450 Rigby will turn out a similar performance level as the .450 Dakota cartridge; this is evident through third-part reloading data provided for the .450 Rigby. Any differences between these cartridges are strictly due to the components use and the pressure level than due to an actual difference between the cartridges.
Cartridge (firearms)
A cartridge, also called a round, packages the bullet, gunpowder and primer into a single metallic case precisely made to fit the firing chamber of a firearm. The primer is a small charge of impact-sensitive chemical that may be located at the center of the case head or at its rim . Electrically...
intended for the hunting of heavy dangerous game. The cartridge is based on the .416 Rigby
.416 Rigby
The .416 Rigby or 10.6x74mm was designed in 1911 by John Rigby & Company of London, England as a dangerous game cartridge and is the first one to use a bullet with a diameter of .416"...
necked up
Wildcat cartridge
A wildcat cartridge, or wildcat, is a custom cartridge for which ammunition and firearms are not mass produced. These cartridges are often created in order to optimize a certain performance characteristic of an existing commercial cartridge.Developing and using wildcat cartridges does not...
to accept a 0.458 inches (1.2 cm) bullet. The cartridge is intended for use in magazine rifles. The cartridge should not be confused with the .450 Rigby Nitro Express which is a rimmed cartridge intended for double rifles.
History
In 1993 Paul Roberts (at the time proprietor of John Rigby & CompanyJohn Rigby & Company
John Rigby & Company, gun and rifle makers, is a firm specialising in the building of high-quality sporting rifles and shotguns.-History:The company was founded in Dublin, Ireland in 1775, and is known to have traded as W. & J. Rigby during the period 1820 - 1865 during the flintlock and percussion...
) was on an elephant hunt in the Zambezi Valley. Both he and his professional hunter, Joseph Wright, were armed with .416 Rigby rifles for the occasion. An elephant was located and then shot in the lungs, but due to a misjudgment in distance several more rounds were required to finally bring down the elephant.
After this experience, Paul Roberts felt that a cartridge with a greater bullet weight of a larger caliber would have been more effective in that situation. Once Paul Roberts returned to the United Kingdom he necked up the .416 Rigby case to .458 caliber. The new cartridge fired the 480 gr of the .450 Nitro Express cartridge at a velocity of 2378 ft/s (724.8 m/s) from a 25.5 inches (64.8 cm) barrel. The new cartridge was named the .450 Rigby Magnum Rimless in 1994. The cartridge was put into production in 1995. The John Rigby & Company was building the .416 Rigby rifles on the 98 Magnum Mauser action. Since the .416 Rigby and the .450 Rigby use basically the same case, building rifles for the .450 Rigby was rather simple requiring only a chamber with a modification made in the collar area and a .458 caliber (11.43 mm) barrel.
Cartridge Specifications
The .416 Rigby which was designed by the John Rigby & Co. in 1911 was one of the most voluminous cartridge cases designed for magazine rifles. By today’s standards it is a rather inefficient cartridge when burning smokeless powder to achieve the desired velocity with a given bullet weight. This is due to the large capacity case which was designed for use with cordite rather than smokeless powder. Consequently, the .450 Rigby, which uses virtually the same case as the .416 Rigby in turn suffers the same inefficiencies. The .458 Lott will use about 81 gr of a powder to reach 2350 ft/s (716.3 m/s) with a 500 gr bullet while the .450 Rigby will use about 99 gr to reach the same velocity with the same bullet. This works out to be about 22% more powder for equal velocity with the same bullet weight. This is due to the larger capacity of the .450 Rigby case which has a case capacity of 133.1 gr. of water (8.64 cm3). However, since the case is voluminous, it is able to turn out this performance at lower pressure levels which is considered beneficial and adding a greater safety margin in a dangerous game rifle cartridge intended for use in the tropics.The .450 Rigby dimensions and specifications are standardized and governed by the CIP.
- CIP compliant .450 Rigby Magnum Rimless cartridge schematic: All dimensions in inches [millimeters].
The CIP recommends a bore diameter of 11.43 millimetre (0.45 in) and a groove diameter of 11.63 millimetre (0.457874015748032 in). Barrel will have a 6 grove rifling contour with a twist rate of one revolution in 420 mm (16.5 in) and a groove width of 3.6 millimetre (0.141732283464567 in). CIP specifies a maximum pressure of 4000 bar (58,015.1 psi).
Performance
Unlike many of the modern .458 caliber dangerous game cartridges like the .458 Winchester, .458 Lott.458 Lott
The .458 Lott is a .458 caliber belted hunting cartridge designed as a replacement for the less powerful .458 Winchester Magnum. It is based on the full length .375 H&H Magnum blown out and shortened to...
or the .460 Weatherby Magnum
.460 Weatherby Magnum
The .460 Weatherby Magnum is a belted, bottlenecked rifle cartridge, developed by Roy Weatherby in 1957. The cartridge is based on the .378 Weatherby Magnum necked up to accept the bullet. The original .378 Weatherby Magnum parent case was inspired by the .416 Rigby...
, the .450 Rigby was designed to operate at more moderate pressures. Maximum pressure limits enforced by CIP is given at 4000 bar (58,015.1 psi). At these pressures, the cartridge easily reaches the intended 2300–2400 ft/s (701–731.5 m/s) with the 500 gr bullet. The lower pressures provide greater operational reliability in tropical environments where the cartridge is intended for use. Heat can cause higher than normal pressures which can lead to difficulty in extracting the spent case. In a dangerous game hunting situation such failures can result in injury or possibly a fatality.
Unlike the .458 Winchester Magnum and to a degree the .458 Lott, the .450 Rigby reaches the coveted 2400 ft/s (731.5 m/s) velocity mark with the 500 gr with ease and well under the pressure limits imposed by the CIP upon the cartridge. Handloaders can take advantage of the wide range of .458 caliber (11.6 mm) bullets available. Acceptable bullets weight range from 300 gr to 600 gr. The 500 gr bullet can easily reach 2500 ft/s (762 m/s) and staying within the pressure limitation imposed on the cartridge.
Among commercial sporting cartridges, only the .460 Weatherby Magnum
.460 Weatherby Magnum
The .460 Weatherby Magnum is a belted, bottlenecked rifle cartridge, developed by Roy Weatherby in 1957. The cartridge is based on the .378 Weatherby Magnum necked up to accept the bullet. The original .378 Weatherby Magnum parent case was inspired by the .416 Rigby...
offers a superior performance over the .450 Rigby. However, most bullets manufactured such as those by Hornady and Woodleigh are rated for .450 Rigby velocities rather than those achievable through the .460 Weatherby. For this reason actual performance and penetration and heavy thick skinned game species are on par between these two cartridges. The Weatherby cartridge has a 6% greater capacity than the .450 Rigby but operates at higher pressures.
Sporting Use
The .450 Rigby was designed primarily to take heavy, thick skinned, dangerous game species. Due to the cartridge’s performance, it would be considered a better cartridge for these game species such as African elephant, Cape buffalo, rhinoceros and perhaps hippopotamus than the usual standby cartridges used on these game such as the .458 Winchester Magnum or even the .458 Lott cartridges especially if one was to use handloaded ammunition. When hunting these game species a bullet of a tough construction is required especially at the velocities the .450 Rigby is capable of attaining. It is important to tailor the performance to the velocity rating of the bullet with regard to this cartridge as it provides a step up in performance over the cartridges the .458 caliber (11.43 mm) bullets are manufactured for. This is especially true for soft nosed bullets as they can open up too rapidly at velocities the .450 Rigby can attain. When hunting these game species only bullets weighting 450 gr of a tougher construction should be used.For lighter game species and other non-dangerous plains game bullets weighing as little as 250 gr are available for handloading. The lightest of these bullets are manufactured for cartridges such as the .450 Bushmaster
.450 Bushmaster
The .450 Bushmaster is a rifle cartridge developed by Tim LeGendre of LeMag Firearms LLC, and licensed to Bushmaster Firearms International for production and distribution. LeGendre still retains ownership of the concept...
or the .45-70 Government and the .450 Marlin
.450 Marlin
The .450 Marlin is a firearms cartridge designed as a modernized equivalent to the venerable .45-70 lever-action cartridge. It was designed by a joint team of Marlin and Hornady engineers headed by Hornady's Mitch Mittelstaedt, and was released in 2000, with cartridges manufactured by Hornady and...
; these bullets may not be best suited for use with the .450 Rigby. Loaded correctly, the .450 Rigby will hit harder and shoot flatter than most big bore cartridge making a good plains game rifle, albeit more powerful a cartridge than necessary for plains game. While the .450 Rigby is too powerful for use against North American game, it is conceivable that the cartridge would provide a powerful stopper against polar and Alaskan brown bear and is equally suited for the harvesting of the American bison.
.450 Dakota
The .450 Dakota is a variation on the design of the .450 Rigby but predates the latter cartridge by a few years. The Dakota cartridge was designed by Don Allen and is like the .450 Rigby based on the .416 Rigby case necked up to accept a .458 caliber (11.43 mm) bullet. The .450 Dakota is considered a proprietary cartridge, the rights to which are owned by Dakota Arms Inc., Remington Arms Company and the Freedom Group family of companies. Neither the CIP nor SAAMI regulate nor have oversight over this cartridge. While dimensions of the cartridges are similar they are not identical and are not interchangeable due to the shoulder dimensions and the case length. The performance of both cartridges are almost identical. However, Dakota Arms' ammunition is loaded closer to 65000 psi (4,481.6 bar).- Schematic of the .450 Dakota. All dimensions in inches [millimeters].
The .450 Dakota launches a 500 gr at 2550 ft/s (777.2 m/s), a 550 gr at 2450 ft/s (746.8 m/s) and the 600 gr at 2350 ft/s (716.3 m/s). While these velocity values are greater than that of the .450 Rigby cartridge, the Dakota ammunition is loaded to near maximum pressure levels while the .450 Rigby is loaded to a pressure level far below the 4000 bar (58,015.1 psi) stipulated by the CIP. Given equal pressure level the .450 Rigby will turn out a similar performance level as the .450 Dakota cartridge; this is evident through third-part reloading data provided for the .450 Rigby. Any differences between these cartridges are strictly due to the components use and the pressure level than due to an actual difference between the cartridges.