I have been viewing my saved photos looking at buttstocks of various muzzleloaders of from various places. What is interesting especially is the classic Muellerbuchse wheellock stock and similarities to it in some crossbows I've looked at and later flintlocks, percussion target rifles,... etc. Also stepped wrist German guns and those buttstocks with a "belly" as you might see on Swiss target rifles etc. Can someone point out a nonsense book or online info that pays attention to the practical aspect of gunstocks as well as the history? It bothers me that I know so little about gunstock design and I think it's time to learn more. Thanks in advance.