Short-period PcP amplitudes have been observed to vary by a factor of about 20 in the epicentral range 40--85¿. This behavior is due to the reflection coefficient at the core-mantle boundary, which varies from a maximum of about 0.5 at an angle of incidence of about 65¿ to zero at an angle of incidence of about 85¿ (corresponding to an epicentral ranges of about 60--90¿). We present physical model experiments in which we study the effect of corrugations of the core-mantle boundary on PcP amplitudes. We find that corrugations with 2--50 km scale lengths would radically alter the amplitude-range behavior of short-period PcP, reducing its variation with range. The observed pattern of short-period PcP amplitudes indicates that the core-mantle boundary is smooth on these scales, with amplitudes less than a few hundred meters.