Bi 2223 tapes have been loaded with current pulses to observe transitions to instability (quench). If a sample is overloaded by a current the magnitude of which is several times the critical current, we find that the time interval during which the sample withstands a quench is longer for samples with smaller critical current densities than for those with larger ones.. The samples developed hot spots, which reduce the resistance against overloading and therefore reduce the dynamic stability of this material.