While I never did deliver ammo for the USPS, I delivered lead balls and bars. The boxes are almost never sturdy enough. Big holes in the corners from the machines and getting thrown around. Or you pick up the box, and the entire bottom rips out. Crap goes everywhere, and you try to put it all back together again but it's a mess. I mean you figure out how to handle it after enough times but the first couple of times you go to pick up the packages like they are normal packages and rip your back out or rip the box open. Then the A$&wipe customer puts a note on it "MUST be delivered to my third floor porch, knock "shave and a haircut", and slide it inside my screen door. Please don't let the ferrets out." Then you just drop it in the driveway and come here and watch somebody post a rant about how the USPS drops their stuff in the driveway but UPS would bring it right to them with a hot cup of coffee and a fresh croissant.