It amazes me that the Russians used shellac. It does poorly around alcohol, including vodka. I work with shellac quite a bit, and it would not be my choice for a rifle finish, especially with Russians about.
I would probably go with multiple coats of tung oil. You can control the gloss by the number of coats, but I don't think you'll ever get to the gloss of the Russain shellac, but I'm not sure if that's a bad thing. I also like Watco's Danish Oil finish but it tends to be more of a satin finish, which is why I often layer it also using tung oil.
If you do use shellac again you might consider using Birchwood Casey gun stock wax. It puts a protective layer on without changing the finish in any significant way. I use a final coat of gun stock wax on all of my finishes, no matter what type.
BTW, if you wish to stain the wood I highly recommend aneline dyes. They can be both water or alcohol based. I prefer alcohol as a base as the stain seems to get deeper penetration. You can also mix them stronger or weaker adding another dimension of control the finish beyond merely how much you wipe on.