|Place of origin||England|
|Designer||Jeffery of England|
|Variants||.404 Rimless Nitro Express, 10.75 × 73 mm|
|Case type||Rimless, bottleneck|
|Primer type||Large rifle magnum|
|Source(s): Norma Reloading Manual, Edition No. 1|
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 × 73 mm. It was created by Jeffery 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 " 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.
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.Kynoch Ammunition. Hornady and Norma of Sweden are also offering .404 Jeffery ammunition.
Commercial and wildcat children
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, as well as the Winchester Short Magnum (WSM) cartridge family, which in turned spawned the Remington Short Action Ultra Magnum (RSAUM) cartridges and the Winchester Super Short Magnum (WSSM) families. Both the Winchester and Remington cartridges have also spawned many current wildcats.
The .375 Dakota by Dakota Arms and the .400 Tembo by Velocity USA, are cartridges based on a .404 Jeffery case.
- Barnes, Frank, Cartridges of the World 4th Edition, p. 329