Finally going to send out an old 77 tang safety rifle for a rebore. I will only be shooting 200 gr. RCBS cast and 220 FN speer boolits. I am thinking a 1-16 twist would get get me the high end velocities out the cast boolits with range mined lead (and alittle1990 WW added if needed). The 3 twist rifling should be adequate for what I plan. Any advice. I have Ramsboot Hunter powder,H4895 powders on hand now. afish4570