picked up the aluminium rod for the pivot pins, string for the sling, and material for the pouch today. jim, i was originally thinking about using golf balls, but they were too big. then i thought about using the .69 caliber round balls that i use in my black powder shotgun, but then i thought that might not be a good idea (costs of glass replacement and possible injuries downrange you know). then i hit on a happy solution, .68 caliber paintballs. perfect counterweight to projectile weight ratio (they recommend a 5:1 ratio, but with a paintball weight of roughly .11 ounces, and a counterweight of 40 ounces (that's 2.5 lbs, not a large bottle of beer) that works out to about a 362:1 ratio. that should be enough to get some good distance and airtime. nice thing about a paintball is they don't bounce when they hit, and it will be easy to step off the travelled distance. mind you now, i did buy a sufficient amount (smaller bags were not available) to allow me a few practice lobs.