Small cartridgeholder with a clip on the back so it attaches to backpacks, belts, rifleslings, pockets etc. Holds on fairly good, but can fall off. Attach so gravity helps, and it will stay in place. I also made a version with a closed loop on the back, which in many instances is a better solution: closed loop 3 round cartridge clip (308) by Walkonwater3D - MakerWorld

Designed for 308win, but a long list of other calibers will fit.

When installing rounds in the clip/holder, pay attention to the lip in the bottom. Put the cartridge at an angle, and all the way to the bottom so the lip in the holder is alligned with the cutout in the cartridge and then squeeze it into the holder.

I have testet printing in both PETG and PLA. PETG is my preffered choice for this part, but PLA sure is easier to print nice.