.505 Gibbs
The .505 Gibbs has a case capacity of 178 grains (11.5 g). This cartridge was originally loaded with 90-grain (5.8 g) of cordite and 525-grain (34.0 g) bullet at 2,300 ft/s (700 m/s) for 6,166 ft•lbf (8,360 J) 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 cartridgeAs .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 inches (12.80 mm) while most other .50 caliber bullets have diameters of .510 inches (12.95 mm). Barnes Bullets and Woodleigh Bullets are a few of bullet manufacturers who produce component bullets for reloading in this caliber. Woodleigh Bullets does not recommend impact velocities of over 2,250 ft/s (690 m/s) for their .505 caliber 525 gr. Weldcore bullets.
Ceska Zbrojovka (CZ) currently manufactures the Safari Classics rifle for this cartridge. Modern semi-automatic rifles are also available in this cartridge from Vigilance Rifles.A-Square, Norma and Kynoch are offering loaded ammunition in 505 Gibbs.
Type rifle
• Place of origin: England
• Production history: Designer George Gibbs
• Designed: 1911
Specifications
• Parent case: none
• Case type: Rimless, Bottleneck
• Bullet diameter: .505 in (12.8 mm)
• Neck diameter: .538 in (13.7 mm)
• Shoulder diameter: .640 in (16.3 mm)
• Base diameter: .640 in (16.3 mm)
• Rim thickness: unknown
• Case length: 3.150 in (80.0 mm)
• Overall length: 3.850 in (97.8 mm)
• Primer type
Ballistic performance
Test barrel length: 24"
Bullet weight/type - Velocity - Energy
• 600 gr (39 g) Protected Point - 2,100 ft/s (640 m/s) - 5,877 ft•lbf (7,968 J)
• 600 gr (39 g) FMJ - 2,100 ft/s (640 m/s) - 5,877 ft•lbf (7,968 J)
• 525 gr (34.0 g) Welded Core SP - 2,300 ft/s (700 m/s) - 6,180 ft•lbf (8,380 J)
Monish