Straight from the Birmingham Proof House, which is the most reliable source I know of when it comes to questions about proof, service pressure etc on British guns:
"The equivalent transducer values that should be used for comparison with SAAMI transducer values are 740 bar service and 960 bar proof, i.e. 10,730 psi (service) and 13,920 psi (proof)."
This was in responce to my post stating the "Older" 3 ton service pressure had been shown by "Simultaneous" crusher & tranducer readings to give an "Actual" reading of about 8960psi.
""IF"" the actual pressures used have not changed then I read that as saying those old pressures were in fact 10,730 "Actual" psi's. Peresonally I need a litle more proof to show they were. I did state verbatin where my figures relating 3 ton to 8960psi derived from. You strongly implied they were all wrong & you had the final word from the Birmingham Proof House. However everything you quoted was for post 80's "Metric" figures. I do not believe these to be totally applicable to the earlier proofs, but could possibly be proved wrong. If so then 10,730 it is.
Miller, I'm a writer. I do this stuff for a living. A review of my previous post--the one you quoted--shows no references at all to anything about guns marked with "tons". However, the paragraph preceding the one you quoted does, in fact, refer specifically to guns with the bars proofmarks. But just to make clear, the only thing I'm certain of is that the 10,730 and 13,920 psi figures are the transducer equivalents for service pressure and proof pressure, respectively, of guns proofed under the CURRENT system.
Thus, you may have INFERRED something from my post, but it was nothing that I IMPLIED. I made that clear in my most recent post, when I said that I would contact the Birmingham Proof House to clarify proof and service pressures for guns from the "tons" and earlier eras. I have done so; currently awaiting a reply.
