Experiments have been made to determine if the unsteady now induced by a streamwise cavity in the nose of a blunt body can reduce mean surface heat transfer rates compared to the same body without a cavity, Measurements were made at Mach 5 and included surface temperatures obtained using an infrared camera, fluctuating pressures at the cavity base, and bow shock visualization using planar laser Mie scattering, Cavities with a length-to-depth ratio of about 2 appear very promising in terms of reduced heating. Cavities for which the length-to-depth ratio varies from about 0.4 to 0.7 exhibit unstable, non-axisymmetric surface temperature and cavity pressure histories. Instantaneous shock visualization reveals nonaxisymmetric shocks that correlate with the unstable pressure histories. Cavity resonance frequency decreases as the cavity depth increases and pressure fluctuations increase in amplitude. In all cases, the primary oscillation frequency agrees well with simple organ pipe theory.