W.J. Jeffery & Co
| .404 Rimless Nitro Express, 10.75 × 73 mm|
The .404 Jeffery is a large-caliber, rimless cartridge designed for large, dangerous game, such as the "Big Five" (elephant, rhino, cape buffalo, lion and leopard) of Africa. Other names for this cartridge include .404 Jeffery Rimless, .404 Rimless Nitro Express, and 10.75× 73mm. It was created by W.J. Jeffery & Co of England based on their desire to duplicate performance of the .450/400 (3¼") cartridge. There are two basically similar sets of dimensions for this case, depending on the manufacturer. The .404 Jeffery as originally loaded fired a .423" diameter bullet of either 300 gr (19 g) with a muzzle velocity of 2,600 ft/s (790 m/s) and muzzle energy of 4,500 foot-pounds force (6,100 N·m) or 400 gr (26 g) with a muzzle velocity of 2,125 ft/s (648 m/s) and 4,020 foot-pounds force (5,450 N·m) of energy. It is very effective on large game and is favored by many hunters of dangerous game. Performance and recoil are similar to other African dangerous game cartridges. The .404 Jeffery was popular with hunters and game wardens in Africa because it gave good performance with a manageable level of recoil. By way of comparison, the .416 Rigby and .416 Remington Magnum both fire a 400 grain .416 in bullet at 2,400 feet per second (730 m/s) with a muzzle energy of approximately 5,000 foot-pounds force (6,800 N·m), which handily exceeds the ballistic performance of the .404 Jeffery but at the price of greater recoil and, in the case of the .416 Rigby, rifles that are significantly more expensive.
.404 Jeffery Wikipedia
Originally the .404 Jeffery was very popular with hunters in Africa and saw significant use in both British and German colonies. As the British Empire began to shrink, many of the popular British big-bore cartridges also dwindled in popularity, and the .404 Jeffery was one of them. By the 1960s it had all but disappeared from common firearm usage. This condition was mostly the result of the closing of the British Ammunition giant Kynoch, which was the primary manufacturer of the .404 Jeffery and many other British cartridges. The introduction of the .458 Winchester Magnum in 1956 in the Winchester Model 70 bolt-action rifle provided an affordable alternative to the big Nitro Express rifles and cartridges and helped to hasten the demise of the .404 Jeffery. Winchester also started a marketing campaign at about this time called "Winchester in Africa" with much success. Renewed interest in heavy game rifles and political stability in Africa has led to a resurgence in African hunting and the rifles suited for it. Kynoch Ammunition has reopened as Kynamco Limited Kynoch Ammunition. Hornady, RWS and Norma of Sweden are also offering .404 Jeffery ammunition.
A more recent development by Norma of Sweden has been the introduction of 450gr ammunition under their African PH banner. The increase in projectile weight and increase in Sectional Density turns the ballistics of the 404 Jeffery into something to behold. Fired at 2150 fps the cartridge now outperforms most of its peers with a still relatively mild recoil due to the efficient design of the cartridge. The ability to do this out of a standard length Mauser action makes it one of the top contenders as the greatest large-medium bore cartridge in existence today. Heavy for caliber components are available from Woodleigh, North Fork Technologies as well as Claw and Dzombo bullets both from South Africa.
In 1908 W.J. Jeffery & Co created the .333 Jeffery by shortening the .404 case, giving it greater taper and necking it down to .333 in (8.5 mm). In 1913 Jeffery's further necked down the .333 Jeffery to .288 inches, creating the .280 Jeffery.
In recent times, the .404 case has seen a resurgence in use by wildcatters. This case has no belt, unlike many other magnum cartridges, which can be desirable for handloading because of possible problems with case head separation with repeated reloading of belted magnum cartridges. The rimless design also contributes to smooth feeding from the box magazine of bolt-action rifles.
Some common commercial children of the .404 Jeffery case are the Remington Ultra Magnum (RUM) cartridge family, which in turned spawned the Remington Short Action Ultra Magnum (RSAUM) cartridges. Also, the Winchester Short Magnum (WSM) and the Winchester Super Short Magnum (WSSM) families are believed to derive from the 404 Jeffery case. Both the Winchester and Remington cartridges have also spawned many current wildcats, like the popular .338 Edge.
All but one (.450 Dakota, based on .416 Rigby) of the proprietary cartridges of Dakota Arms such as .375 Dakota, and the .400 Tembo by Velocity USA, and the once-famous .460 G&A, used by Jeff Cooper in his "Baby" rifles, are all based on .404 Jeffery.
Another example of the popularity of creating small-bore, high velocity cartridges based on .404 Jeffery design is the .26 Nosler, .28 Nosler, .30 Nosler and the latest .33 Nosler, introduced by Nosler in between 2013 and 2016.