Hello,
I have been playing Avadon for some weeks now and I have finished the game.
Concerning enchanting, I have noted that neither rings, nor projectil weapons can't be enchanted.
I am not shure if it is a bug or was on purpose but I find it too bad you can't enchant a bow with a stone that gives better critical chances when put on a weapon... espcially if you have built a character focused on bow (with high dex).
Hope it gets fixed in Avadon 2