The .500 Nitro Express is a centerfire cartridge created in Great Britain. It is a .510 caliber (13mm) big bore hunting cartridge. It was intended for use in double and single shot breech-loading rifles.
The cartridge comes in two lengths: 3.00 inch (75 mm), and 3.25 inch (83 mm). It was intended for large and dangerous game species in India and Africa.