A couple things about your particular stock job comes to my mind. The Beretta O/U stocks usually have at least a decently thick wrist if not overly thick on the later clays models, so strength issues in the wrist get some help here, as opposed to a thin wristed sxs. Secondly, if you're stock will be a long LOP and you want a lightweight stock, you might consider looking at "Claro" walnut blanks. These will run lighter in weight than english walnut by a lot. They can have some of the prettiest colors and figure of all the walnuts. Your gun being a 20g and a stout wrist size, should handle Claro fine. Alternatively, black walnut from the central U.S. will be heavier than Claro, but lighter than English walnut. Black walnut has the highest strength/weight ratio (generally).
