The tray supports 7 aluminum STANAGs or 6 staggered PMAG 30s. Included pistol magazine caddy (single and double versions) support Glock magazines with a bit or room to spare. I've not tested them with other makes or models. Double magazine caddy hangs 5mm below the stack plane and should only be used on the tray nearest the ground to avoid contacting attachments below it. The AICS Utility Caddy supports two AICS pattern magazines with room to spare for small parts and can double as miscellaneous storage. Tray connectors are included to connect horizontally stacked trays, if desired.

Dovetail connectors provide 2mm of clearance. They prevent detachment, but are not tight. I recommend not stacking higher than two trays with loaded magazines. I've not stress tested the tolerances.

Print Settings (printed on Creality K1C with hyper PLA)

Stackable Mag Tray - Infill 25%, with supports 

All Mag Caddy Variants - Infill 25%, with supports, ensure to print such that mag openings are to the ceiling to avoid unnecessary supports.

Connector - Default Infill, no supports

Note

I used this project to teach myself CAD and use my new 3D printer. It's my first project and it's imperfect.