The behaviour of a carbon fibre - epoxy composite has been investigated as a function of specimen thickness. Results show that both the shock velocity and the shock stress are unaffected by transit distance. The relationship between U(s) and u(p) over the range of measurements made in this investigation shows a higher value of c(0) and lower value of S than that of a similar material within the literature. We believe that this is due to the slightly higher proportion of carbon fibres within the microstructure reducing the compressibility. Differences between the Hugoniot stress and the calculated hydrodynamic pressure suggests that the shear strength of this material increases with shock stress.