The R100 box is a flip top box and will hold 100 rounds of ammo. I took out the plastic and it has molded in supports. I cut the squares of wood to 3.145" give or take a whisker. I probably should have done this last night but didn't feel like it. This morning I took a pic to give a better idea of what and how. The wood is some cherry I had laying around and had to glue 2 pieces together to make it thick enough to use.
Sam