A new method of investigating adiabatic shear band velocities under hydrodynamic pressure is described. Interpretation of propagation rates depends on an appreciation of the stress and strain fields into which propagation occurs. The C-HEMP computer code has been used to characterize load histories, and results are described for comparison with the adiabatic shear bands observed. A quantitative dependence of adiabatic shear band velocity on pressure is suggested, and the indication is that pressure alone can be a significant influence on adiabatic shear band behavior.