This is a 3d-printable potato cannon projectile I made a while back. It is meant to print in two pieces with supports and later be filled with something heavy, I used some gravel, before getting screwed together. It was fired out of my 12bar 44mm potato cannon and did way better than a potato ever would, maxing at about 450-500m of range. And yes it does spin nicely in flight and i did some simple aero simulations on ot for fun!

Remember: Potato cannons are dangerous, only play with things that don't involve risk for you and others.