I turns out I made a slight miscalculation when measuring out the first unit. I sized it to an old ammo can which is about a half inch longer and a quarter of and inch taller. Oops!
I just finished version 2.0 that drops into a standard modern 5.56 can. I also managed to squeeze in 16 dowel rods as compared to the 14 on version 1 for a 480 round capacity. This piece of wood stained very badly so I ended up just painting it flat black. I made a few other small build modifications to speed up construction time.
There is enough room left over for a few moon clip tools between the handle and the stacks.
Next mission is to figure out a setup for the half sized belted 7.62 cans. The holdup right now is devising a sturdy handle that does not take up too much space.
My next mission is to size one for smaller ammo cans