CIP “Standard Proof” is for lead OR STEEL (limited to no larger than 3.25 mm / U.S. No. 4s and max. fps 1,300) ie. target/game loads, and without choke restriction (but I still wouldn't use full in a light weight game gun)
https://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=598636

This is from the Gamebore site

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