When a British shell box is labeled:
These cartridges are suitable for use in:
70mm case length: Guns with a chamber length of 2 3/4” or longer, nitro proofed to a service pressure of 3 1/4 tons per square inch (900 kg per square cm)
67 mm case length: Guns with a chamber length of 2 1/2” or longer, nitro proofed to a service pressure of 3 tons per square inch (850 kg per square cm)
The CIP transducer “Maximal Statistical Individual Pressure” of 850 BAR is for a “Maximal Average (Service) Pressure” of 740 BAR = 10,733 PSI
900 BAR is for a “Maximal Average (Service) Pressure” of 780 BAR = 11,313 PSI
