A simple analytical model is presented to describe the delay τcbetween flashlamp initiation and laser-pulse onset in the flash-photolysis HF chemical laser. The predictions of the model agree well with experiments concerning the functional dependence of τcon pressure, flashlamp intensity, optical cavity loss, and the absolute magnitude of τc. This detailed agreement between theory and laser performance has not been achieved in previous chemical laser work. The pulse-delay measurements demonstrate the presence of complete vibrational inversion at the time of laser-pulse initiation. In the Appendixes, the fractional photodissociation of MoF6is calculated for the experimental geometry used, the effects of flashlamp heating are considered, and a general expression for the temperature dependence of HF laser gain is derived and plotted. A complete bibliography of laser transitions in HF and DF is included.