.223 Rem. (5.56 x 45 NATO)

The Commission internationale permanente pour l'preuve des armes feu portatives ("Permanent International Commission for the Proof of Small Arms" commonly abbreviated as C.I.P.) is an international organisation which sets standards for safety testing of firearms. (The word portatives ("portable") in the name refers to the fact the C.I.P. tests small arms almost exclusively; it is ordinarily omitted from the English translation of the name.) As of 2015, its members are the national governments of 14 countries, of which 11 are European Union member states. The C.I.P. safeguards that all firearms and ammunition sold to civilian purchasers in member states are safe for the users. To achieve this, all such firearms are first proof tested at C.I.P. accredited Proof Houses. The same applies for cartridges; at regular intervals, cartridges are tested against the C.I.P. pressure specifications at the ammunition manufacturing plants and at C.I.P. accredited Proof Houses.