I have been casting with Lee aluminum double cavity molds for over 30 years. For round balls I cast .440, .454 and .530. Keep your lead at the right temp and you will not get wrinkles. If you are casting for a muzzle loader, be sure to use pure lead. Wheel weights cast hard, but are fine for modern firearms. My supplier has been F&M reloading:
http://www.fmreloading.com/ . Double cavity Lee molds with handles go for $16.58. Best price I have found.