STACKABLE 5.56mm NATO AMMO BOX FOR 50 CALIBER CAN

This was inspired by another 5.56mm NATO stackable box. The other model had thin walls internally which were too flimsy and often the slicer reversals would fail to bond the filament at the intersection of the single-wall partitions. The design also let the ammo rest on the bullet tips, which I did not like for premium match-grade ammo. So I fixed it!

My design uses a bit more plastic than the design that inspired it, but puts 1mm walls between rounds and is designed to suspend the ammo at the primary case taper so the bullet tips don't get deformed rubbing in the storage box. These boxes will fit neatly in a standard 50 BMG ammo box, 3 along the length, 2 wide, and 3 high.

*UPDATED 2023-August 1 * Finally I have finished the 5.56 NATO "reduced plastic" version like my 6.5 Creedmoor design. Greatly reduces the amount of filament needed per box. Prints as a mostly-hollow box, lid, and 2 plates to provide the needed spacing. Plate 1 goes in the bottom with variable-height side up. You need to prop one side on the lower ledge then let the plate drop into place, then push down to snap into the slot. Plate 2 inserts in the same manner, you can leave "pretty side up" for this one as it is symmetric top to bottom. MAKE SURE TO ALIGN THE HOLES. Plate 2 and plate 1 must be in alignment. There are 2 ways they can be oriented, only one is correct. This should be obvious when you compare them to each other.

I have found that even on my Bambu X1C & P1P with WhamBam build plates, a brim is needed on the box part. There is a notch along the bottom that interlocks with the lid of the box stacked next to it, using the lid ridge feature that also assists in sliding the box lid open. My attempts at printing without the brim on the box have always resulted in knocking the narrow bit loose before the printed pieces join together just a few millimeters up. A brim helps keep this from happening. This part starts at about 2mm wide on the base plate and grows to 5mm when it joins the rest of the box. Enabling brim (5mm) seems to fix it. You just need to trim it away when done for proper interlocking.

The new design says it uses about 70 grams less plastic, from 178
down to 108 grams!

I built this on a Bambu Lab X1 Carbon with a 0.4 mm nozzle using tri-color co-extruded PLA, but any number of materials will work. ABS is probably a better choice for toughness. Use your favorite material. I would not use expensive filament as even with 10% infill, it uses 178 grams of filament for the box and lid.
I printed with 0.2mm layer height, 3 wall loops, 4 top shell layers, 3 bottom shell layers, gyroid or rectilinear infill, no brim or supports. Your slicer might complain about the unsupported overhang due to the notch on the bottom, but this can be ignored with adequate cooling.