A bull we have had some success with on heifers is AMAA# 378168 BPF SLAM DUNK 78T. These calves have been generally born weighing 70-75# with small heads, very vigorous and coal black colored. They feed really well as far as Maines go and I wouldn't mind having a whole lot full of them the way they have performed for us. I did have a 100# calf one time by a cow that had a history of having big calves no matter the sire, but have not had problems calving moderate BW heifers to him.