"As for CIP numbers, per the latest information I have--which comes from the British Association for Shooting and Conservation--it now appears that velocity is measured at 2.5 meters."
"I'm betting that 1450 figure is true muzzle velocity."
This is consistent how? Is not Hull Cartridge actually governed by CIP standards?
Adhering to CIP standards does not mean all member countries arrive at those standards in the same way. Here's a very good example: Starting in 1989, the British proofhouses started using a proofmark that expressed the proof pressure of the gun in bars. For 12 bores, standard proof was expressed as 850 bar; magnum/superior as 1200 bar. A bar = 14.5 psi (or actually a bit more, but 14.5 is close enough for govt work). However . . . in 1989, the British proofhouses were still measuring pressure by the old crusher methods: lead crusher for lower pressures, like shotguns; copper crushers for higher pressures, like rifles. That confused a lot of folks on this side of the pond, because we thought you could multiply those numbers x 14.5 and get a figure comparable to our own psi figures--which were measured with electronic transducers, not crushers. Then, in the early to mid-90's, the British (and at least some of the other CIP countries) switched from crushers to transducers. However, the British did not change their proofmarks--even though 850 bar crusher = 960 bar transducer. (And once you get to the 960 bar figure, you can then multiply x 14.5 to get the correct psi equivalent.) All of which is a long way of pointing out, via an example, that the CIP does have common standards, but that does not mean that they all express pressure or velocity figures in the same way. And when it comes to velocity, that's not a question of a CIP standard anyhow, except in the case of steel shot loads. As long as the shell in question conforms to CIP PRESSURE standards--which they all do, if they carry the CIP stamp of approval--then you're good to go. For that matter, the same thing applies to American shotgun shells and SAAMI standards: there isn't any velocity standard, only a pressure standard.
But we are far less complicated on velocity than the Brits, because we ALWAYS express velocity measured at 3 feet unless clearly specified otherwise.
