That is the European version of our SAAMI specifications for cartridge design.
So if I was to buy a 6.5-47L reamer and it says (CIP), that would be ok?
Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives (Permanent International Commission for the Proof of Small Arms)
For the most part their standards are interchangeable with SAAMI, but be careful, some cartridges (see the delta L problem https://en.wikipedia.org/wiki/Delta_L_problem ) can be problematic.
Also, CIP allows higher pressure for some older cartridges than SAAMI.