Impact is considered on a rod of finite length whose material exhibits viscoplastic behavior described by a power-law relation between strain rate and dynamic overstress. Strain-hardening and elastic strains are neglected. Solutions previously obtained for the linear case are supplemented by deriving upper and lower bounds for the final strain. The general solution for the nonlinear case, with strain and stress assumed uniform along the rod, is derived and compared with results of the complete solution. The general solution for uniform strain is also compared and contrasted with results of the simplest rigid-plastic (rate independent) theory involving plastic wave propagation.