doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Measuring pressure: Crushers to transducers

Obviously correct. Proof loads are designed to generate whatever pressure the authority in question (CIP or SAAMI) has determined to be the pressure to which guns passing proof under their standards should be subjected. Those loads are pressure tested in pressure guns. The loads are then fired in the guns subjected to proof testing. If they don't blow up or show any other changes when carefully inspected, they've passed proof.

Similarly, shells for general use are also pressure tested by ammunition manufacturers, and must conform to the service pressure standards (significantly lower than proof pressure standards) established by either SAAMI or CIP for general use.

I have emailed the Birmingham Proofhouse. Awaiting a reply.

Re British proof: Conforming to CIP standards is an issue which does not relate directly to the proofmarks used in CIP countries. For example, although the UK joined the CIP in 1980, they continued to proof their guns at the same level they had been proofing them previously (expressed in "tons"--a language which only the British and Americans speak!) Those proof rules remained in force until 1985. There was a transition period, 85-89, when British guns could be marked either with the old "tons" proofmarks or the new "bars" proofmarks. Those proofmarks (850 bar standard, 1200 bar magnum/superior) were values derived via the old lead crusher measuring system. If, per the quote in a previous post, the "modern electronic equipment" refers to electronic transducers, then that means they switched to transducers in 1992--but continued marking their guns with crusher-derived pressure values until 2006!

Once more I should stress that 1200 bar crusher and 1370 bar transducer are THE SAME PROOF PRESSURE. It's only a question of whether one can multiply a bar (or kg) value times 14.5 to come up with the equivalent psi value. You multiply bars/kgs measured by a lead crusher x 14.5, you get LUP rather than psi. That's the issue in question, rather than an actual change in the proof pressure to which guns were subjected when measured with crushers vs transducers.