I tried 3031 10 grains and reduced the black to 70 and blue dot, and the 3031 worked the best and both really cleaned up the barrel and brass. I think I am going to have the gunsmith regulate the 600 at 100 grains of black and the 700 or so grain bullet. I am going to order the mold from Jim, Allison once the barrels are slugged.The only real decision i have to make soon is whether to use magtec brass (2.5) of RMC who will make 3 or 3.5 brass. If i go to the longer brass, will I have to increase the load much and recoil?