I have a dozen or so 50 cal ammo cans. Stackable, sturdy, air tight.
They're a little heavier empty than one of the plastic equivalents, but I've never heard of anybody ever complaining about the handles coming off of one.
Dang heavy when you top one of those puppies off, though...which is why I have one labeled "Range". I just drop whatever I intend to shoot in it and go.