Another example. 1888 J. Blanch reproved in 1999 (Crown over R) using Nitro Powder (according to an e-mail with the Birmingham Proof House) for; Service pressure 740 BAR = 10,733 psi; Maximum statistical individual pressure 850 BAR = 12,328 psi. Courtesy of Greg Baehman.
Drew--I think you slipped up on your conversions of bar pressure readings to psi. 740 bar is the transducer equivalent of the crusher-measured service pressure of 650 bar, so you're OK there. But that 850 bar mark is proof pressure also as measured by the crusher method; therefore, needs to be converted to the transducer equivalent. And that is 960 bar transducer, or 13,920 psi.
I'd also note that there are plenty of examples of British guns that have been reproofed--as is quite clear from 2 or more sets of proofmarks--without the crown over R reproof mark. I'd say there are probably more guns that have been reproofed without being stamped with the crown over R than with it.
Last edited by L. Brown; 12/13/16 12:28 PM.
