tkthorn, how large is the sprue hole in your 2 inch mold? It should be at least 1/4 inch for a ball that size, 3/8 would be better. In casting almost any metal the faster the mold is filled the better will be the casting. but, if you can't get the metal into the sprue hole fast enough it doesn't matter how big the hole is. If possible, make the entrance to the sprue into a funnel shape large enough to pour the metal fast without spilling it. Usually, with a small sprue, a lot of metal misses the hole and winds up on the ground or on the outside of the mold and this causes wrinkles in the balls because the stream of molten metal is being broken. You want to cast the ball in one continuous pour. l cast balls into the cold mold until I start getting good ones without wrinkles, returning the bad ones back to the melting pot.