Silicone rubber processability problems can be Very costly. New methods have been developed using the RPA 2000 Rubber process Analyzer to improve sensitivity to these problems, identify the,,assignable causes of variation" and take the necessary corrective actions. These test methods measure differences in dynamic viscosity, shear thinning behavior, and elasticity differences which have significant effects on the way these compounds process in plant production. The effects of variations in average molecular weight, and molecular weight distribution of the base silicone polymer as well as particle size and surface chemistry of fumed silica loadings were studied.