UPDATE 3/18/24: I have split this into two models, the box and the lid. I have also made it taller to better accommodate different types of ammo. These I've uploaded as STL files. 

Thank you everyone for your feedback.

This is a simple ammo box I designed for 300 Blackout.

I used normal supports for the lip over hang and the base lip. I tried organic but the proved difficult to remove and left the lip sort of chewed up.

I didn't really need these. I bought ammo in bulk and wanted something more than just loose rounds in a cardboard box. Also I am learning Fusion360 and this was a fairly simple project to learn on.

Is this the best ammo box out there? Probably not. Is it the best it could be? Also probably not. Am I happy with the way it turned out? Absolutely.