My Merkel 16 bore O/U shotgun was proofed in 1933 and has 65 mm chambers and is in excellent condition. Question what would be the maximum service pressure for shot shells that I would load/fire in this Merkel? I have not seen or missed German shot shell max service pressures listed based on gauge and chamber length.
Is this information accurate? "From Larry Brown's recent communication with the Birmingham Proof House, I thought an addendum should be placed at the end of this thread in case anyone is saving it for future reference:
**650 bars is standard CIP (British and European) service pressure for shells designed for guns proofed at the CIP standard of 850 bars**
European (CIP) proof pressure of 850 kg per sq. cm. (BAR) = 13,920 psi proof pressure= 10,730 psi service pressure (SAAMI)
Per the 1954 Rules of Proof, here are the equivalent service pressure values:
3 tons--8,938 psi
3 1/4 tons--9,682 psi
3 1/2 tons--10,427 psi
4 tons--11,917 psi
These numbers SHOULD apply to guns proved under the 1925 rules, which were stamped only with chamber length and shot charge. Thus, a 2 1/2" chambered gun, 1925 rules of proof, would be equivalent to 3 tons; a 2 3/4" chambered gun to 3 1/4 tons.
A service pressure of 3 tons per sq. in. = 8,938 psi service pressure (SAAMI)"
Thanks!
Jim
