According to The Standard Directory of Proof Marks, the Crown over U was brought in with the first Germanicon standardized proof laws of 1891, and was "a final or definitive proof, also on guns proofed in the finished state, and then marked with the Crown over B stamp"

The Crown over B stamp "is the proof mark applied to a gun that has undergone proof in the finished condition. Crown over U mark must also be present"

Both marks continued in usage with the modified proof laws of 1912, but were done away with with the new proof laws of 1939. So, these marks were in use both pre and post WWI. I have seen them on Mauser pistols and commerical sporters, etc. So, not a lot of help in narrowing things down. I note that my pre-war Mauser sporter in ".30 US" has a 5 digit number and these two proofs.

Logic would dictate that this would have to be a pre-WWI or immediate post WWI rifle, as it has the older features. I would expect that any rifle put together after the war, especially if using existing parts stocks, would have the grasping groove on the forestock and the bolt take-down hole in the buttstock. Once the Czechs started making and marketing the VZ24 and the Belgians the similar FN equivalent, everyone went with the flatter tangent rearsight, so I can't see a lot of effort being put into utilizing Lange-Viziers on new production rifles after about 1925........

I suspect that sail32 is correct and this is a pre-WWI offering to the commercial and "interested small dictatorships" market, but maybe we'll never know.

I'm leaning more towards my Canadianicon/Britishicon/Frenchicon stuff these days, and am most likely going to offload the bulk of my German collection, but this is a cool old rifle so it might be a keeper! It's funny, because it was part of a lot of rifles at the spring Rock Island Regional Auction, where it was not well described; it wasn't the rifle I really wanted in the lot, but I'm having more fun with it than I am with the one I had been really after.

Ed