An experimental technique is described for obtaining high rate tensile stress-strain data on materials with limited ductility. A modified split Hopkinson bar apparatus is used to obtain data on three advanced structural grades of beryllium at strain rates up to 500/sec. The data indicate that there is no significant loss in ductility with increasing strain rate in any of the three grades of beryllium. Flow stress is shown to increase linearly with strain rate up to strain rates of 1-10/sec and then more abruptly at higher rates.