Could you use one of Berry's handgun cartridge boxes or one of their 20 gauge shotgun shell boxes for larger diameter bullets stacked 2 high with a thin disc of cartboard between them?
the consolidation of the states into one vast republic, sure to be aggressive abroad and despotic at home, will be the certain precursor of that ruin which has overwhelmed all those that have preceded. Robert E Lee ~Molɔ̀ːn Labé Skýla~
Do you or a friend shoot handguns? Thinking Winchester had hard foam for the rounds to sit in. You could cut it down with a hacksaw blade ect. Not sure what caliber would work. But hopefully you get the idea. Good luck