All the round ball ammo I buy now seems to be forged rather than cast, so there are no sprues. However I still have a bunch that I bought years ago for my 1860 Colt replica that were cast. I've heard both ways sprue up and sprue down recommended over the years. I suppose aerodynamics is what makes the difference? Is accuracy affected? The advice I was given 50 years ago when I bought my first BP revolver was sprue down so that's what I've always done.