I created multiple versions of some trays to hold 45acp ammo in retail boxes. 

Per the file names:
The SM is a smaller tray for smaller boxes.
The LG is slightly larger for larger boxes.
The ‘Tall’ are 4mm taller than the ‘Short’. Both hold good, I just made the shorter for quicker printing.
The 25 round holders are exactly half the size of the 50 round so 2 will fit in a box. I mainly made those as my resin printer wasn't big enough for the large 50 round tray.

I print these in resin. I tried one on my FDM printer, it turned out ok, but the fit was worse for the ammo and print quality of all the small towers wasn't very good. Maybe it just needed to print slower.