.577 Nitro Express

The .577 Nitro Express is a rimmed cartridge in the Nitro Express series of big-game hunting ammunition. It is also known as the .577 Nitro Express 3" and there is a variant called the .577 Nitro Express 2.75". The .577 is notable as the standard caliber of professional ivory hunters in the 19th and early 20th centuries.

History
The .577 Nitro Express was descended from the .577 Black Powder Express, a cartridge invented by the late Samuel Baker who had Holland & Holland build him an express rifle in this caliber. It began as a black powder round, and then became a smokeless round. It fires a 750-grain bullet (about 48.6 grams) at a muzzle velocity of around 2050 feet per second (625 m/s). The 2.75 in. version, intended to duplicate the black powder version, launches a 650-grain bullet at more than 1950 ft/s, depending on the type of powder and amount used.

Rifles
A few manufacturers still make rifles chambered in 577 Nitro Express due to its popularity including Hartmann & Weiss, Heym, Holland and Holland, Butch Searcy & Co., James Purdey and Sons, Westley Richards, and Hambrusch Hunting Weapons.

Hunting
This caliber is generally used for thick-skinned dangerous game such as elephant, rhino, and Cape buffalo. Even among professional ivory hunters of old it was typically treated as an emergency weapon carried by the hunter's gun bearer, reserved for stopping the charge of an enraged, wounded elephant in thick bushes rather than as a day-to-day hunting weapon. Legendary elephant hunter James Sutherland carried a .577. Count Alfred Józef Potocki, Ernest Hemingway, and Stewart Granger also carried .577's.

It is unnecessarily powerful, harsh recoiling, and unwieldy for use against lesser game. For this purpose the old black powder version can be used. It throws a 560-grain bullet at around 1700 ft/s.

The .577 Nitro Express as a parent cartridge

 * .577 Tyrannosaur: Created by Arthur Alphin of A-Square Co. as a replacement for a bolt-action .577 Nitro Express.
 * .585 Nyati: Made by blowing out the .577 Nitro Express case and turning the outer edge of the rim so it is slightly rebated, making it a "rimless" cartridge.
 * .600/570 JDJ: Created by SSK Industries; made by necking up the .577 Nitro Express to accept .620 inch diameter bullets from the 600 Nitro Express.
 * .620 JDJ: Created by SSK Industries; made by shortening the .577 Nitro Express case to 2 inches and necking it up to accept .620 inch diameter bullets.
 * 14.5 Whisper: Created by SSK Industries; made by shortening the .577 Nitro Express to 2 inches. Designed for subsonic accuracy with heavy bullets.