In the Lore of Beasts, you find the hunter's spear spell, and it's writen: "The spear goes through ranks of the target in the same way as missiles from a bolt Thrower. Does it do D3 wounds as well(just as a bolt thrower?)
Is says "goes through ranks of the target in the same way as missiles from a bolt Thrower", not "does wounds exactly like a bolt thrower", so it could be arguable.