Two similar elastomers of known difference in processability are examined by means of the MTS high speed tensile tester and the Mooney rheometer at a low speed. The samples are butadiene‐acrylonitrile copolymers having 42% acrylonitrile content. Measurements on the MTS tester are made at −35, 24, and 85°C and cross‐head speeds of 2.5, 25, and 250 in.∕sec. These speeds correspond to strain rates of 468, 4680, and 46,800%∕sec, respectively. In addition, measurements are made at 100°C and 2.5 in.∕sec. A Mooney rheometer is used to obtain shear stress‐strain curves at 100°C and 0.05 rpm. Both tensile and shear stress‐strain curves are used to construct master curves, which cover 17 decades of the deformation rate. A major difference between the samples is found in the low rate range of the observation. The ultimate properties are also examined. Rather small sample‐to‐sample differences are observed in the stresses at break.