.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 0.416 in. The rifles, as built by John Rigby & Co., were initially made up on Original Magnum Mauser actions although in later years, some were made on standard length actions, a perfect example being the rifle used by legendary professional hunter Harry Selby. Other famous users of the cartridge were Commander David Enderby Blunt, John Taylor and Jack O'Connor.

Origin & History
Two major developments at the turn of the 20th Century set the course for the development of the .416 Rigby as a successful rifle cartridge. The first was the development of cordite in the United Kingdom in 1889 and the development in Germany of the Gewehr 98 magazine rifle.

Prior to the invention of cordite, rifles used gunpowder (black powder) as a propellant. Due to the burn characteristics of black powder it did not produce high pressures and therefore did not produce high velocities. Big bore cartridges of the era were the 4 bore, 6 bore and 8 bore rifles cartridges. Sub 0.50 in Caliber were considered small bore cartridges. Although the 4 bore, 6 bore and 8 bore cartridges were considered appropriate for dangerous game during that era, these cartridges lacked the penetration required to take heavy thick skinned game such as elephant, buffalo or rhinoceros humanely. The development of smokeless powder revolutionized the rifle. One version of this smokeless powder developed in the U.K. was cordite which allowed higher pressures to be developed and thereby increasing the velocity of bullets. The invention of smokeless powder rendered the big bore rifles of the era to be relegated to obsolescence. With the emergence of cordite as a propellant what was considered a big bore cartridge changed to any cartridge having a caliber of over 0.458 in. The switch during World War I to modern smokeless powders would cause what constituted a big bore to be further refined to mean any cartridge over 0.400 in.

Next improvement was the development of the Gewehr 98 rifle by Paul Mauser. Paul Mauser did not invent the bolt action rifle but rather he refined the design allowing controlled round feeding, magazine feeding using a stripper clip, and a strong action with the ability to withstand high pressures generated by the new smokeless powders. The rifle design would go on to become the most common and successful rifle design in the history of firearms. During World War II most Axis and Allied nations with the exception of the British (Lee Enfield), and the Russians (Mosin-Nagant) used rifles based on the Mauser 98 action. Today this is still the most popular rifle design and is used to this day by Mauser, Dumoulin-Herstal, CZ, Holland & Holland, Kimber, Rigby, Ruger and Winchester among others. The Mauser 98 action provided the consumers and gun makers an inexpensive alternative to the double and single shot rifles which until that time predominated the dangerous game hunting scene.

At the turn of the 20th Century, three major British rifle manufacturers, Jeffery, Westley-Richards and John Rigby & Co. designed cartridges which could operate in the Magnum Mauser action and could offer big bore nitro express ballistics and performance in a magazine rifle which was what the British called their bolt action rifles. The result was the .404 Jeffery, .425 Westley-Richards and the .416 Rigby. While these cartridges were considered to be the new medium bore cartridges during their day, their performance on game matched the performance of the big bore Nitro Express cartridges. The performance of these cartridges was due to the sectional density (greater than 0.300 in) and higher velocity (~2300 ft/s).

The first .416 Rigby rifles used the Magnum Mauser Square Bridge No. 5 action. The large bolt face and the length of the Magnum Mauser No. 5 action was easily adopted for use with the .416 Rigby cartridge. As the Magnum Mauser action became scarcer after World War II, .416 Rigby rifles were built on Enfield P-17 and the BRNO actions instead of the Magnum Mauser action. Both the BRNO and the Enfield P-17 actions are in turn based on the Mauser 98 rifle.

After World War II with the dwindling of areas to hunt dangerous game, interest in the .416 Rigby cartridge and most big bore cartridges began to wane. By the 1970s with the demise of the British ammunition supplier Kynoch as an entity, the supply of .416 Rigby ammunition was dwindling, and many hunters including Selby set aside their .416 Rigby rifles taking up the more popular .458 Winchester Magnum or the .375 H&H Magnum.

Between 1912 and the beginning of World War II John Rigby & Co. produced just 169 .416 Rigby rifles and 180 between 1939 and 1984. Between 1984 when Paul Roberts took the reins of John Rigby & Co. and 1997 when the company was purchase by Geoff Miller’s investment group 184 more rifles were produced. It was not until Bill Ruger of Sturm Ruger Co. began offering the Ruger Model 77 RSM Magnum Mk II in the 1991 that the cartridge finally took off. Ruger produced approximately 1,000 rifles between 1991 and 2001, dramatically boosting the number of .416 Rigby rifles in circulation.

With renewed interest in dangerous game hunting in Africa, and the renewed demand for .416 Rigby ammunition, ammunition manufacturers Federal, Hornady and Norma began producing ammunition to meet the new demand. The Kynoch brand name was licensed by Eley to Kynamco a British ammunition manufacturer, based in Suffolk England, which continues to manufacture .416 Rigby ammunition under the Kynoch brand name.

Design & Specifications
The .416 Rigby cartridge case is one of the most voluminous designed for a magazine rifle. The case was originally designed to utilize cordite strands invented in the United Kingdom as a propellant. The large case allowed the .416 Rigby to operate at what today would be considered moderate pressures, yet turn in a good performance with regard to velocity and energy. Like many of the big bore cartridges designed during the early 20th century, the .416 Rigby was intended for use in Africa and India. As cordite burnt hot and was susceptible to high chamber pressure variations dependant on ambient temperature, the relatively moderate pressure loading by today’s standards of the .416 Rigby provided a safety margin against dangerously high pressures when used in tropical regions.


 * [[Image:416Rigby.png|600px|alt=416 Rigby Cartridge Schematic|.416 Rigby CIP cartridge dimensions - all dimensions in mm (in)]]
 * CIP compliant .416 Rigby cartridge schematic: All dimensions in millimeters [inches].

The .416 Rigby’s dimensions and specifications are governed by the European Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives (CIP) which mandates compliance by member nations to these published dimensions and specifications. The CIP mandates a 6 grove barrel with a bore diameter of 10.36 mm and a groove diameter of 10.57 mm with each groove being 3.60 mm wide and a twist rate of 1 revolution in 420 mm. Commencement of rifling is to begin at 7.62 mm. CIP stipulates a maximum average pressure of 325 MPa for the cartridge. At present the North American Sporting Arms and Ammunition Manufacturers' Institute (SAAMI) has not provided recommendations for the .416 Rigby.

Performance
The original ammunition for the .416 Rigby used cordite as a propellant firing a full metal jacket or soft point round nose weighting 410 gr at 2300 ft/s generating 4702 ftlbf. The current standard using smokeless powder is a 400 gr bullet at 2400 ft/s generating 5115 ftlbf. This is the standard to which Federal, Hornady and Winchester load their ammunition. In its original configuration, the .416 compares favorably with its close counterparts of the era: the .450/400 Nitro Express, .404 Jeffery and the .425 Westley-Richards. The .416 Rigby loaded with the 400 gr bullet at 2415 ft/s as the Hornady’s DGS and DGX ammunition are, has an MPBR of 198 yd. The cartridge is capable of producing over 4000 ftlbf of energy at a range of 110 yd. In comparison the typical .458 Winchester Magnum firing a 500 gr bullet at 2050 ft/s manages to stay above the 4000 ftlbf just past the 50 yd mark.

Since the late 1980s several .416 cartridges have come to the market. Among these the .416 Remington Magnum, the .416 Ruger and the .416 Weatherby Magnum have garnered the most attention of the firearms press. Both the Ruger and Remington cartridges were designed to emulate the Rigby cartridge’s performance level of a 400 gr bullet at 2400 ft/s. When loaded to their respective maximum average pressure level both the Remington and Rigby cartridges are capable of driving the 400 gr bullet at over 2500 ft/s. However, the Rigby cartridge is loaded to the relatively low maximum allowable pressure of 325 MPa while the Remington cartridge has a stipulated maximum average pressure of 430 MPa. The case capacity of the Remington case is about 82% of that of the Rigby cartridge. The larger case of the Rigby allow the cartridge to generate the same velocity and energy as that of the .416 Remington but does so at far lower pressure levels. Unlike the Remington and Rigby cartridges, the .416 Ruger due to its case having even less capacity then the Remington operates an near its peak allowable pressure to emulate the performance of the Rigby and Remington cartridges’ factory ammunition. The .416 Weatherby Magnum which uses a case of similar size as the Rigby is capable of launching the same bullet at 2700 ft/s.

Sporting Usage
When designed the .416 Rigby was intended for use against dangerous game in Africa and India. The original 410 gr bullet has a sectional density of .338 and at a velocity of 2300 ft/s generated 4702 ftlbf. The energy generated by the cartridge was on par with that of Rigby’s earlier .450 Nitro Express which, until the ban on the 0.458 in caliber in India and the Sudan in the early 1900s, had been the standard of measure for dangerous game rifles. The .416 Rigby would in its own right go on to become one of the most successful dangerous game cartridges designed for a magazine rifle.

Jack O’Conner, the noted advocate of small bore high velocity cartridges, took a .416 Rigby on his African safari and successfully took elephant and lion with it. Professional hunters such as John “Pondoro” Taylor, David Enderly Blunt and Harry Selby used the cartridge extensively for the hunting and the culling of elephant and Cape Buffalo. Today the .416 continues to be one of the favored rifle cartridge carried by professional hunters in Africa. J.A. Hunter provided a testimonial to John Rigby & Company stating “You will be pleased to know that the rifle which accounted for all the rogue lions on my last Government Expedition was the 416 Bore Magazine Rifle you supplied me with. I cannot speak too highly of it. Its stopping power was extraordinary, and the fact that all the lions, rhino, buffalo, etc., were shot at comparatively short range, and no other rifle to back me up, speaks volumes for the accuracy and efficiency of your rifle.”

While considered overpowered for the big cats, the .416 is regularly used for the hunting of these felines. In African nations which have enforced a ban on the use of sub 0.400 in rifle cartridge for dangerous game, the .416 Rigby is one of the first cartridges which can be considered for the hunting of lion or leopard. Prior to India’s independence in 1947 the .416 had success against India’s dangerous game which included the Bengal tiger. However, even the largest of the wild felines weigh no more than 660 lb and are thin skinned species and for this reason cartridges in the 0.338 in caliber magnums are more appropriate for these species. When using the .416 Rigby to hunt these large felids lighter bullets weighing 300 - 350 gr which open up rapidly or fragment similar to the A-Square Lion Load are the most appropriate.

Until recently, the use of .416 cartridges was mostly confined to Africa, where they were used primarily on dangerous or "thick-skinned" large game such as rhino, elephant and Cape buffalo. The .416 Rigby would be considered overpowered for North American game species. However, the .416 Rigby does offer a greater insurance against polar bear, Alaskan brown bear, and useful for the hunting of American bison where allowed.

As a Parent Cartridge
The .416 Rigby cartridge case is of a unique design in that it had no prior cartridge case acting as a parent cartridge during its development. Due to the volume of the case, the .416 Rigby case has gone on to act as a parent cartridge to several modern cartridges and provide the inspiration to many others. The .378 Weatherby Magnum family of cartridges which include the .30-378, .338-378, .378, .416 and the .460 Weatherby Magnums use a case similar to the .416 Rigby albeit with a belt added to the case design.

The .416 Rigby is the parent cartridge for the following cartridges:

.300 Lapua Magnum
The .300 Lapua Magnum cartridge was designed by Lapua of Finland using the .338 Lapua Magnum case which in turn was base on the .416 Rigby. Lapua does not manufacture ammunition for the cartridge and should be considered a wildcat cartridge.

.338 Lapua Magnum
The .338 Lapua Magnum cartridge is a redesign by Lapua of a prior designed by Research Armament Industries (RAI) and Brass Extrusion Labs Ltd. (BELL) known as the .338/416. The Lapua uses an modified .416 case shortened and necked down to accept a 0.338 in bullet. The cartridge is capable of firing a 15.0 g bullet at 920 m/s.

.450 Dakota
The .450 Dakota was designed by Don Allen of Dakota Arms. It is virtually identical to the .450 Rigby which it predates by a few years. The cartridge is based on the .416 Rigby necked up to 0.458 in. The .450 Dakota fires a 500 gr bullet at 2550 ft/s.

.450 Rigby Magnum Rimless
The .450 Rigby was designed by Paul Roberts of John Rigby & Company. The cartridge was designed to fire a 480 gr bullet at 2378 ft/s.