Here are some pics and measurements from a set of box components that Mark Lachney had made for some of us.
The minimum interior height should accommodate a can of your favorite powder. Mine is Goex, which I think is 6 1/2 inches high. Check this measurement as it is critical!
My box is 11 inches across which allows for stability and it can hold two longguns and a range rod across it front. It is also 15 inches long.
The front wall extends 1 1/2 inch below the floor in order to hold the box at the edge of your loading bench to support your long guns while being loaded. See the side view of the box. This is an important feature to remember during construction.
There is an interior partition which makes a powder compartment at the rear for two cans of your favorite powder. This also strengthens the box. This is glued and then screwed with counter sunk screws.
A lower wall makes a spearate partition a bit forward to separate your ammo and accoutrements. I made mine lower, but some people want it deep for greater strength. I set these based upon loading blocks that I used at the time. Customize this for your owns needs.
The flap out to the front has cuts to accommodate two guns, a set of 5 round balls in .50 cal (If I had to do this over, I would router a groove rather than cut the opening as I went from mostly shooting .50s to .40s and those drop through!) a hole for a short starter and an L shape cut for your range rod.
I found the latch and most other hardware at Lowes. I added corner protectors and used some nice hinges and a bit of chain to hold the flap when it is open. Leather would work.
I hope that some of this is helpful -- I turned the box on its side to show the underflap which seats the box onto the loading bench when I heard the ugly sound of two different size ball containers dump their balls into the box! :shocked2: These are .403s and .395s. I am debating tossing the into the lead pot or getting out the micrometer...
CS