I doubt you will have much luck with mulberry for a rifle stock, although it can be a incredibly beautiful wood when polished down to fine detail. I have seen it in this form and it is really something in its own class. The Japanese really like it for making decorative items, arty and display stuff. Although a hard wood and a dense, it soft but splits easily when put to work or nailed. It also twists considerably and is far too lively for a stock.
There are far better woods for your need.
OH, it also takes very long to dry properly.

I wood look at Tamboti or Mopani if I were making a South African rifle stock, both are dense hard and stable enough, both finish really nice - REALLY.
Both are a bit heavy if you a woosey though, very heavy wood.

Treeman, thanks. I am slightly worried about the twisting of the wood.

There are some african wood types which can be used, like drolpeer (Dombeya rotundifolia). There used to be a stock maker in Nylstroom who did it.

I have read or heard that tamboti does not stand the recoil. The other thing is to get a large enough piece. If someone knows more I'd appreciate it.

On searching the net, I have come across some rifles with mulberry stocks, so I am pushing ahead for now.