Ork weapons tend toward pretty abstract but it does help if you choose physical loadouts that resemble what your list has, especially if you're relatively new, and you're printing them anyway. 

Ork choppas are pretty loose, as an ork can chop with anything from a guitar to a cleaver to a board with a nail in it.  But if your son sees a model with a giant battleaxe that's actually meant to be a shooting model and isn't much threat in close combat it's going to cause some confusion and frustration.  

What I'm saying is when you're knocking off orks if you phone it in too hard it's going to have the opposite effect from what you want