Miller,
I wasn't trying to sharpshoot you, it was just my "wordy" way to explain the early date and what seemed to be a long chamber. As far as I know, whether it was dated or listed the ledger number, was a proof house decision, not mandated by law. You are correct that early smokeless( voluntary nitro)proofs had to follow BP rules for the amount of powder used in the proof loads. It is true that some guns that were really intended to use nitro powder were submitted for BP proof. Also, some were submitted for nitro proof, but for a smaller duty load than was intended for use. As far as your gun having a 70mm chamber, the proof houses proofed the guns for nonstandard chamber lengths on request. This was fairly common on guns for export. If the gun had a standard chamber the size(caliber) was enclosed in a circle. Non standard chamber lengths( either shorter or longer) had to be marked with the nominal chamber length in mm(if export maybe inches). The proof load being shown on the gun, showing bore diameter in gauge measurement, and without chamber length for rifles, calculating smokeless proof load weights, under the 1891 law( effective early 1893) caused a lot of confusion and improvements were made in an attempt to clear up the confusion, in 1911. The significance of the 1912 date is that was when the 1911 improvements became effective. I did note that your bore( not groove or bullet) diameter was shown in gauge measurement(pre 1912), but the chamber length was shown( post 1912). There are a couple explanations for this, but I think it may have been by request, since it was for export to VL&D. I hope I didn't confuse matters.
Mike
