Tell us about yourself!
I don't think this would launch a 90kg projectile over 300 meters
Is that a 90kg projectile flying 300 meters?
Pretty cool, but can it use a stone counterweight to launch a 90kg projectile over 300 meters?
well... you can buy them here http://www.ebay.com/itm/Tamiya-08-Module-Steel-Pin...or if your like me and have many rc parts and old rc cars laying around then just salvage some from those.