Dartfly that is made specifically for the .50 caliber foam paintballs.
Sides need to be glued on.
The foam ball didn't stick with e6000 when I tried. I used super glue instead.
Regular or rubber paintballs most likely would work as well, but would not be as clean/soft.
remix of https://www.thingiverse.com/thing:4697569/remixes
The author remixed this model.