Just got my new RCBS charge master combo yesterday. It performs as advertised, getting the powder weight within +/- 0.1 grains of what I want. I had been using a balance beam scale with some tweezers pulling out or adding a spec of powder at a time. I feel that was more accurate than the electric charge master, although it takes longer. I guess my question is how accurate does a load really need to be in order to shoot well?