These combine for lower numerical readings than US radial crusher gun CUP and lots lower than piezo psi. Pre-metrication British chamber pressures are:Ģ, Measured with an axial crusher gauge with element in a modified bolt head, not a radial gauge with hole in barrel. "No accurate conversion between crusher and true pressure exists, but approximations can be made" I'll quote a guy who appears to know a lot about it.
When they began changing over to a newer system they had to settle on a number to use in the conversion formula because they couldn't figure how the old system complared to the new one. The problem appears to be that way back when they used a Lead Crusher Radial system to proof firearms. "Per the 1954 Rules of Proof, here are the equivalent service pressure values:Īnyway, 6 times 8,938 psi = 53,628 psi = 18 "tons" per square inch, about right for a 30-06. I found this quote several times while searching for "British proof": This sort of confusion is what happens when you apply common sense and logic to British measurements. I was thinking the same, myself, but what do I know? I'm just an American and those blokes speak English, a rather peculiar language. Why would your barrel bear an Anschluss proof date of 1936 when the takeover of Austria did not happen until March of 1938? The thread: There's something 'screwy' about this. So your rifle was not sitting in stock, already proofed, since the 1920s, but was assembled and proofed in 1939.
Only from then on guns made in former Austria were marked with the German eagle/N proofmarks and the German month+year dates. 39 date was not applied by the Steyr factory, but by the proofhouse. So the former Austrian proofhouses, Vienna and Ferlach, continued to use their procedures and stamps until the new, 1939 law, proof rules became valid on April 1, 1940. A new German proof law was already worked on. After Austria was annected (with much applause by many Austrians, a fact now forgotten by them) by the 3rd Reich on March 12, 1938, not everything changed immediately. In fact this alone dates a gun to 1938 – 39. The combination of "Made in Germany" and Austrian NPv or NPf proofmarks is not unusual. The thread is well worth a read: Also, from another thread: From 1940 to 45 the Vienna, Ferlach and Weipert proofhouses used the then new German proofmarks. After the "Anschluss" it replaced the single headed eagle with hammer and sickle in the claws, the symbol of the 1918 - 1938 Austrian republic.
This eagle for primary proof was used only for a short time, from 1938 to 1940.
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