The term axe is only in its name,which also confers its status as unique,but the rules in the BA codex clearly state that it is a powe weapon. The BRB then says that a power weapon which is unique,master crafted making it so, is treated as being a AP3 power weapon. Just my opinion,and until its clarified as good as any. As a matter of fact as I see it,there's more support to it being a AP3 Weapon than there is otherwise