I found a nice program for calculating muzzle loader ball ammo. You can also use it to calculate foot-pound force for round slingshot ammo.
http://www.ctmuzzleloaders.com/ctml_experiments/rbballistics/ballistics/ballistics.zipFor sight height, use the distance between the forks on your slingshot divided by two, if you shoot it sideways. Use 0 if you shoot it upright. You'll need to know the speed of the ball (muzzle velocity). You can calculate that if you have a camera that records video and you know how many frames per second the video is. Just count the number of frames it takes to leave the slingshot and hit the target. You need to know the distance too. Speed = Distance / Time
http://tryconvert.com/sconvert/framespersecondframespermillisecond.htmlSteel ball weight chart:
http://bearingballstore.com/index.php?main_page=page&id=6Remember, try to only hunt within the range where the ammo still has 10 foot-pounds of energy or more.
