I'm weighing options for my first centerfire bullet mold purchase, after digesting several posts here (thanks for the points to ponder folks). This will be to make plinking, training, and "rabbit" rounds, so accuracy also would be appreciated. This is as some may know a .328 diameter 105 grain SWC with six cavities. A search on this forum with the Lee mold number gives no results for me.Not cheap for a new caster, it's about $40. Have looked for the twist rates of my GP100 and 77/357 to see if they are the same. Still looking, but believe that would be vital information. This load would save on lead, and make for a fun round with mild recoil. BC is .106 but I don't know how to use this figure. I'm trying to learn from past posts here and elsewhere methods to choose a slug. Thanks. Don