I have had my best results with a midget 358-477 looking boolit from an old LBT mold. IIRC, it is marked 315-100 SWC. Sized .313 over 11.8 grains of H-110, and a CCI 500 primer, it shoots great. I have managed several 1" groups with it in my 7.5" Single Seven, though it averages more like 1 1/2." In my SP 101, it does well also, but I can't shoot the shorter barrel as well. In the boolit line up, the two on the right-RCBS 32-98 SWC, Lyman 311-008--were too long if crimped in the crimp groove to use in my Single 7's, but do work in the SP 101. The stubby SWC in the middle is the best performer.