Also, and again someone likely has an exception, but the "70/20.6" which is chamber length & dia just ahead of the rim seat, both in MM's is "Normally" found only on those guns receiving the optional Nitro Proof, ie Lion/PV. It was not a requirement on those guns proofed only with Black Powder proofs.


Miller/TN
I Didn't Say Everything I Said, Yogi Berra