Experimental potato cannon round, 50mm, Mark III

Experimental potato cannon round Mark III fits barrel of 2 inch PVC DIY potato cannons (50mm). Its special shape should provide smooth airflow and rotation that self-stabilizes and prolongs the flight of projectile. The Mark III version has all the updates of Mark II (https://makerworld.com/en/models/2143889-experimental-potato-cannon-round-2in-50mm-mark-ii) and on top of that it is whistling and has grooves for O-rings to improve fit in barrel. (smaller one is designed for 2mm cross section O-r