Miller, you might want to do a bit more research into CIP. The Brits are members of the same INTERNATIONAL proof organization as the French, German, Spanish, Italians . . . almost every major country in the world where guns are actually made (except ours, where SAAMI operates on somewhat similar principles, with differences previously noted in this thread). So British proof is definitely recognized by other countries.
Craig, sometimes my posts are long enough without explaining everything, so I sometimes omit things which, to me, are obvious. Reproof and consumer education . . . If there's a requirement for reproof, then the consumer will eventually be aware of that requirement. Even as consumers are aware of the law that prohibits car dealers from turning back odometers. So, say a gun has had its chambers lengthened from 2 1/2" to 2 3/4". When that happens, the gun receives reproof marks indicating that it is now 2 3/4". Given the presence of those marks, would you not say the consumer is now more "educated" on what shells he can safely use in the gun in question? It's a much shorter and more concise version of the owner's manual that you get with a car, or with various other things you may buy. The owner of the gun no longer has to guess whether Bubba lengthened the chambers without submitting it for reproof. It's now right there, stamped in the metal, plain as day, for him to see. Just like the "19" on my Sauer tells me that the gun left the factory overbored in comparison to standard 20ga bore diameter. In both cases, the owner knows more about it than he would without those proof/reproof marks. All of which is good, IMO.
