Thanks Bob,
Would you know of what powder is equivilent to the original Gewehr Blattchen Pulver (military flake powder) as a lot of these have the load data marked on the receiver ring. I have also read that the proof house at Zella-Mehlis introduced new proof rules on september 1, 1911 and the proof house at Suhl, in april 1912, adopted the Zella-Mehlis rules. According to the new regulation, smoothbore and rifled barrels were tested with special proof powders which were produced by the Koln-Rottweiler Pulverfabrik (Cologne-Rottweiler Powder Works). So how does one know how to translate these over to the common powders of today to know if they were proofed for the higher velocity magnun bombe? I started loading on the light side and worked up to 2500 fps range for the std loading and watching for pressure signs along the way. (Fine) I have been afraid to work up higher due to the beautiful stock on my rifle for fears of inducing a crack.

M4220