I made this for a coworker who wanted a flat case holder that holds 100 casings. The grid is 10x10. Printed at 20mm layer height, with 15% infill, and two walls, you're looking at just over 300 grams of plastic, allowing for 3 trays per 1 kg spool.

Use a brim, the model is flat and has large surface area. Chamfers and rounded corners are added to help with warping, but are not a total fix. You will have some degree of very slight warp, unless you've tuned your printer better than me, in which case you have nothing to worry about. To account for this, attach small foam sticky pads at all four corners on the bottom. This not only gives the model grip, but negates the very slight warp you'll likely have. Without these, there's JUST enough warp where it looks good, but spins like a top on a flat surface.

Enjoy! If you need one in .308, check out my page. I made another one just like this one for the same coworker.

Printables Tags: 223cal; reloading; 300blk; 223rem; reloadingtools; 300blackout; 223; 223remington; bullet