The .700 Nitro Express is a big game rifle cartridge made by Holland & Holland, London, England. It was developed in 1988 by Jim Bell and William Feldstein and built by H&H. Feldstein had tried unsuccessfully to get H&H to build a .600 Nitro Express for him, but they had already ceased production. However, when Bell and Feldstein produced the entirely new .700 Nitro Express cartridge, they were able to attract the interest of H&H, who was looking for a new big-bore cartridge. After production began, the backlog of orders was so great that it continues to this time (2007) and H&H has even restarted the production of .600 Nitro Express guns.
In many respects this cartridge parallels the .600 Nitro Express, in that it is essentially a scaled-up version of that cartridge, but is somewhat more powerful, and fires a heavier 1000-grain (64.8 g) bullet. The case itself is a completely new case, not simply another case resized. Double rifles are extremely expensive (many will sell for US $60,000 or much more in 2005 American currency) and have generally been replaced by magazine-rifle rounds like the .458 Winchester. Single factory loaded .700 Nitro cartridges are available, typically at $100 each, although they have been sold on the internet for as little as $50. This round, like many other big bore cartridges, can be hand reloaded, drastically reducing the cost - although few users are likely to expend much of this massively-recoiling ammunition.
While the .700 Nitro Express is sometimes claimed to be the "most powerful commercial round in the world", by the manufacturer, this is not exactly true. The .700 Nitro Express double rifle is only available on a custom order basis, and has never seen regular production, while the .585 Nyati which is built under similar circumstances is significantly more powerful. Currently the most powerful rifle cartridge available on a commercial basis is the .50 BMG. It is also referred to as the most powerful sporting cartridge in the world. The largest caliber sporting cartridge is a wildcat 2 bore cartridge which fires a 3500 grain 1.326" diameter projectile generating 17500 ft-lbs of energy
The .700 Nitro Express develops an approximate average of 8900 foot pounds (12 kJ) of muzzle energy with a 1,000 gr (65 g) bullet at 2,000 ft/s (610 m/s). However handloaders can push the cartridge to generate as much as 15,000 ft·lbf (20.3 kJ) in a modern bolt action, by using a 1,000 gr (65 g) bullet fired at 2,600 ft/s (792 m/s). However, doing so makes the action of the rifle used nearly inoperable (especially in the case of a boxlock or sidelock rifle), while at the same time rupturing the cartridge casing and the primer cap.
The typical average muzzle velocity of a factory-loaded cartridge is 2,000 ft/s (610 m/s). In the 14-pound rifle used by Accurate Reloading this would result in recoil energy of approximately 196 ft·lbf (266 J). This is more than ten times the average recoil from a .308 Winchester which is a very common hunting caliber, and more than twice the recoil of a strong .45-70 Government round.