The "Hardness" of the bullets you cast will also help in sizing. The more tin you add to the mix will make a bullet harder,and smaller. A softer mix,(less alloy) will cast bigger. The Lee ram sizers will do a good job,and you don't have to buy a sizer/luber to use them,just your press. As mentioned above gas checked bullets are easier to get along with,more so if you push them a little harder. On the mold blocks look for the letters GC as this indicates the bullet is made for gas checks. Ron