.505 Gibbs

The 505 Gibbs cartridge was designed by George Gibbs in 1911. The cartridge was originally known as the .505 Rimless Nitro Express or simply as the .505 Rimless. CIP 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 rifles.

General Information
The .505 Gibbs has a case capacity of 178 gr. 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 standard of 2,700 bars (39,160 p.s.i.) for the cartridge. As .505 Gibbs was intended for hunting dangerous game in a tropical environment and due to the temperature sensitivity of cordite the lower pressures provided 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 2250 ft/s for their .505 caliber 525 gr. Weldcore bullets.

Premium dangerous game rifle manufacturers, such as Hartmann & Weiss (Hamburg, Germany) and Westley-Richards (Birmingham, UK) build expensive but thoroughly 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. Modern semi-automatic rifles are also available in this cartridge from Vigilance Rifles.

As of 2013, Norma, Nosler and Kynoch are offering loaded ammunition in 505 Gibbs. Excellent bullets are available from Cutting Edge Bullets, Woodleigh Bullets, and North Fork Bullets.

Design & 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. CIP has published specifications for the cartridge.


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

The CIP requires that a barrel have 5 grooves, twist rate of a bore Ø of one revolution in 406 mm, a bore Ø of 12.55 mm and a groove Ø of 12.80 mm with each grove measuring 5.33 mm wide. The recommended pressure for the .505 Gibbs is 2700 bar.

Sporting Use
The .505 Gibbs is a niche cartridge, designed for hunting heavy, dangerous game, such as elephant, cape buffalo and grizzly bear.

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.