The narrower Plano ammo cans (the green plastic ones) at the local farm and home store. They were on sale for $6 a piece. I prefer my old milsurp metal ones, but at that price, I figured what the hey!
I like the Plano boxes and have seveal. I also have some metal surplus boxes that I know for a fact are at least 45 years old. Those things are near indestructible.
Indeed, those old milsurp ones can take a beating (and give a beating to whatever they bump into or fall on). These are a little easier to work with and don't scratch everything they sit on. I was surprised the price was this good, honestly.