How big is a slingshot steel ball without drifting

8 millimeters. According to the query related to public information, the slingshot steel ball is used 0.65 thick flat leather taper 20 to 14 with 7.5 to 8 mm steel ball, the ballistic is very stable, if with 7 mm and below, the initial velocity is very fast, close range power is also very large, but long-distance distance is somewhat drifting, basically can't see the trajectory beyond 15 meters, and thus not good to adjust the accuracy, so it's not very suitable for hitting the long-distance. Flat leather band to play how big marbles suitable to look at the flat leather band tension and length, different thickness and width of the leather band tension is not the same. For example, 2 kilograms of tension to play 6.5 of the ball, 2.5 kilograms of tension to play 7 to 7.5 of the ball, 3 kilograms of tension to play 8 or so of the ball, 4 kilograms of tension to play 9 to 10 of the ball, 5 kilograms of tension to play 10 to 11 of the ball, 6 kilograms of tension to play 12 of the marbles.