James, well I wish I could say it ain't so, but DJ is right. I have yet to be able to drive cast bullets above 1300 fps with the accuracy falling apart. the only exception has been the Magnus Bullet Co. #704 300 grainer. I can drive it to 1450 with no trouble but the cost would prohibit it being a plinker. I have found that as a general rule, the POI will only change vertically form one load/bullet weight to another once a zero is established. You might want to put a low power scope on it, tape a setting chart on your stock and shoot away, forgetting the matter of the front sight height altogether. sounds like you have found a couple of nice loads to play with, thats great.