The wiki article seems to provide a clue, referring to pressure testing prior to 2006. That's an interesting date, because it's also the date of the latest change in British proofmarks. Since 2006, the British proofhouses no longer use any numerical pressure markings, having replaced them with STD (standard) and SUP (superior). But the Spanish proofhouse was using transducer values several years prior to that.
Another possibility is that although some countries (England) continued to stamp crusher-derived pressure values on their guns (850/1200 bar), they may in fact have changed to transducers at an earlier date but did not change the proofmarks to conform to transducer-derived values.
Every time I think it's getting clearer, it gets murkier. If even their transducer system is different than ours, then it would seem that it would not work to convert their bar/kg readings to psi by multiplying x 14.5. Or at least you would not get the same psi reading derived from our transducer testing.
Last edited by L. Brown; 01/11/14 09:27 AM.
