CIP 12g 50mm, 60mm, 65mm, and 70mm “Standard Proof” lead or steel (limited to no larger than 3.25 mm / U.S. No. 4s and max. fps 1,300)
Numbers are transducer BAR converted to PSI.
Maximum Average (SERVICE) Pressure 740 BAR = 10,733 psi;
Maximum Statistical Individual Pressure 850 BAR = 12,328 psi
Mean PROOF Pressure 930 BAR = 13,489 psi
(The original 1984 chart, which was revised in 1990, indicates 12g PROOF 960 BAR = 13,924 psi. The number was revised to 930 BAR)

12g “High performance/Superior Proof” (and 3” & 3 1/2”)
Maximum Average (Service) Pressure 1050 BAR = 15,229 psi
Maximum Statistical Individual Pressure 1200 BAR = 17,405 psi
Magnum proof 1320 BAR = 19,145 psi

Magnum proof was originally 1370 BAR but was lowered to 1320 about 2006.

12g STEEL regulations: the barrels carry the High Performance Steel Fleur de Lys stamp that Ted posted and are marked “Steel Shot”

Gamebore

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Shell box warning

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