There is some walnut that is softer than beech (e.g. black walnut) and some that is harder (e.g. brazilian walnut). The term "blonde" is usually used in conjunction with birch when the sap wood is being used for making a stock. Birch core wood has a darker reddish/brown color much like beech.
I'm aware there are lots of Mauser rifles with beech stocks but those are typically not "blonde".
I've done a lot of work with VZ58 wood which is beech, easy to work with and takes stain reasonably well. I've seen mostly Elm for M48 stocks and have had good experiences with them so far... I really like my walnut VZ24 Mauser though.
Birch... is hard to work with, doesn't take stain well.
That VZ24 of yours is a real beauty. Yes, birch doesn't take stain well. It tends to come out blotchy if you don't seal it before staining.
I know this is a bit of topic... but it shows the different colors of birch. These are some rustic half log benches I make from birch. They are oiled and it makes the different colors of the core/sap wood pop out.
Any photos or range reports yet?
For those still wondering what beech looks like - this VZ24 handguard is european beechwood.
Note the characteristic light coloured crescents in grain. These areas don;t take stain and don't absorb oil to oxidize dark. This is a universal characteristic of beech.
I've only ever seen a couple beech stocked M48's over the years, the very vast majority were Elm. I've seen more early walnut stocks than I have beech. I sometimes wonder if Branko got Beech and Elm mixed up when he wrote his book, or if the translator he was working with mixed them up.
Keeping it real on the range since before there was a CGN.