.505 Gibbs

The .505 Gibbs cartridge was designed by George Gibbs in 1911. The cartridge was originally known as the .505 Rimless Nitro Express. The C.I.P. refers to the cartridge as the '''505 Mag. Gibbs''' in their publications. It is a .50 caliber (12.8 mm) rimless bottlenecked cartridge intended for magazine-fed rifles.

General information
The .505 Gibbs has a case capacity of 178 gr of water. This cartridge was originally loaded with 90 gr of cordite and 525 gr bullet at 2300 ft/s for 6166 ft.lbf of kinetic energy. While the .505 Gibbs has a greater case capacity than most modern cartridges, it is loaded to lower pressures. The C.I.P. recommends a pressure of 2700 bar for the cartridge. As .505 Gibbs was intended for hunting dangerous game in tropical environments, and due to the temperature sensitivity of cordite, the lower pressures provide a greater safety and reliability margin.

The .505 Gibbs has a unique bullet diameter of .505 in while most other .50 caliber bullets have diameters of .510 in. Barnes Bullets and Woodleigh Bullets are a few of the bullet manufacturers who produce component bullets for reloading in this caliber. Woodleigh Bullets does not recommend impact velocities of over 2200 ft/s for their .505 caliber 600 gr weldcore bullets.

George Gibbs Ltd. (England) continues to manufacture .505 Gibbs rifles; other premium dangerous game rifle makers, such as Hartmann & Weiss and Westley Richards build expensive and reliable .505 Gibbs rifles on Mauser 98 actions.

Ceska Zbrojovka (CZ) currently manufactures the Safari Classics rifle for this cartridge. Doumoulin Herstal SA of Belgium offers the cartridge in their White Hunter model.

As of 2019, Federal, Kynoch, Norma, and Swift are offering factory loaded ammunition in .505 Gibbs. Bullets for reloading are available from Barnes, Cutting Edge Bullets, North Fork Bullets, and Woodleigh Bullets.

Design and specifications
The .505 Gibbs is one of the most voluminous cases designed. The large volume was required as the cartridge was designed to burn cordite as its propellant. The C.I.P. has published specifications for the cartridge.


 * [[Image:505GibbsMagnum01.png|500px|alt=C.I.P compliant schematic of the .505 Magnum Gibbs|C.I.P compliant schematic of the .505 Magnum Gibbs - all dimensions in mm (in))]]

The C.I.P. recommends that commencement of rifling begin at 8.97 mm. Bore diameter is given as 12.55 mm and groove diameter is 12.80 mm. The C.I.P. recommends a five groove barrel contour with each groove having an arc length of 5.33 mm and a twist rate of one revolution in 406 mm. The recommended pressure for the .505 Gibbs is 2700 bar.

Sporting use
The .505 Gibbs is a niche cartridge designed for hunting heavy, thick-skinned dangerous game animals, such as cape buffalo, elephant, and rhino.

In literature
The cartridge's claim to fame was its use by the fictional character, Robert Wilson, the hunter of Ernest Hemingway's short story "The Short Happy Life of Francis Macomber".