The shock sensitivity of a new pressed formulation based upon CL‐20 has been studied. Samples were made from a biomodal particle size distribution of the CL‐20 εpolymorph and an EVA binder, pressed to an average 97% of theoretical maximum density. The material exhibited an anomalous reversal in slope of shock sensitivity vs. input stress. Over a limited stress range near the first reaction threshold, the level of reaction decreased with increasing input stress. Within this range of input shock it was observed that break‐out of reaction was delayed, and was concentrated near the sample centerline.