I have no experience in the field of cast bullets,but Texas by God gave me a variety of some for my 30-30.I already have some jacketed 170s loaded up with different charge weights to test in a couple days,and I thought about slapping together a few of the cast as well.Will I need to start out on a freshly brushed barrel when switching to cast,or vice versa?..I have been looking at some old data for cast, and 4064 is probably what I will charge them with,because I don't have 3031 on hand. The data I am looking at seems to favor loads of 23-24 gr. 4064 for most weights of bullets from 115-180.Does this seem light?.All the bullets that Tex sent me have gas checks and fall into these weights..Thanks