Temperature
All laboratory tests were undertaken at a temperature of 60°F / 20°C. However, higher temperatures as experienced in the tropics, will possibly affect pressure. As a rough guide, if climatic temperature doubles, then pressure increases by approximately 10%. During testing in England in 1991, our .416 Rigby cartridge was subjected to variations in temperature. The results obtained were as follows:

60°F/20°C	2305 ft/sec	14.1 ton / 2177 bar /33935 psi
20°F/-40°C	2301 ft/sec	14.0 ton / 2186 bar /33933 psi
100°F/60°C	2305 ft/sec	17.1 ton / 2626 bar /38070 psi

As the maximum pressure allowed for the .416 is 18 tons, even under increased temperature the cartridge is still within permissible pressure limits.

Barrel length
All Ballistical data was obtained from barrels with an average length of 24". A 1" variation either side of this length, will result in a 30ft/sec increase or decrease in muzzle velocity.

Conversion table

1 psi = 0.06895 bar	1 grain = 0.0648 gramm (g)
1 ton = 23.9 psi	1 ft/lb = 1.36 joule
1 bar = 14.5 psi	1 ft = 0.3048 m
1 ton = 154.445 bar

Metallic ammunition
The ammunition is designed for use only in standard arms specifically chambered by the manufacturer for the cartridge and so inscribed on the barrel.

Shotgun cartridges
Do not fire Westley Richards shells in guns having Damascus or other twist steel barrels of chambers shorter than shell length designated on box. Use only in arms in good condition and in proof and designed for modern ammunition of this gauge. If doubt exists, check with gun manufacturer. Before loading make sure the barrel is not obstructed, especially that no shell of smaller gauge has lodged in the barrel. Failure to comply with these warnings may cause serious accident with injury to the shooter or bystanders.

Wear proper hearing protection. Repeated exposure to gunfire can damage hearing. Wear shooting glasses to protect eyes. Reloading of these shells is hazardous and should not be done.