Ammo Box Military outlet Vintage Item

We have an Ammo Box Military Vintage Item. It measures about 12" in w x about 7 5/8" in h x about 6 1/8" in d. One side is marked in yellow paint the other side in depressed letters on the bottom (pls see photo's). It does close, outlet it was closed with a nail through the small hole in the center of the box securing it when I attained it. There is a fair amount of rust and overall wear showing on this item.