The .450 No 2 Nitro Express is rimmed, bottlenecked, .458-inch (11.6 mm) calibre cartridge designed for use in single-shot and double rifles, it fires a 480-grain (31 g) projectile at over 2,175 feet per second (663 m/s).

[3][4] The .450 No 2 Nitro Express has a massive 3.5-inch (89 mm) long cartridge case which has a large case capacity and compared to other similar Nitro Express cartridges has a thicker rim and heavier walls.

[3][4] Following early extraction problems encountered with the revolutionary .450 Nitro Express which had been created by John Rigby & Company in 1898, Eley took the unusual step for the time of creating their own completely new cartridge and release it to the market in 1903, allowing all rifle makers to chamber weapons for their round.

[3][4] Following the British Army 1907 ban of .450 caliber ammunition into India and the Sudan, Eley developed the .475 No.

Other notable users of this cartridge include Philip Percival who hunted with a pair of .450 No 2 Nitro Express boxlock double rifles made by Joseph Lang, and Nripendra Narayan, Maharaja of Koch Bihar, who hunted with a large battery of rifles including a .450 No 2 Nitro Express double rifle by Manton & Co.[3][5][6]