The dynamic fragmentation of coarse and fine grained granitoid blocks during impact has been exam- ined for energies of 1.9 kJ to 3.0 kJ and 2.7 kJ to 6.8 kJ, respectively. A particle tracking algorithm was developed to measure ejecta size and velocity at the rear of the tar- get for a horizontal railgun arrangement. Fragments for the finer-grained material are smaller than the coarser-grained specimens as a result of enhanced comminution of fractured surfaces and increased intergranular fracture. Length scales > 6 mm contain > 80 % of the total mass and kinetic energy. Median ejection velocities increase for increasing impact energy (range from 5 m/s to 10 m/s for both materials). These are low in comparison to incoming projectile velocity (250 m/s to 500 m/s) and indicate that the bulk of incom- ing energy is dissipated into forms other than kinetic energy transfer (e.g., heat and comminution). Approximately 25 % of the mass and 80 % of the kinetic energy is contained in velocities >20 m/s. The total conversion of impact energy to ejecta kinetic energy is estimated as approximately 3 % for the coarser material and 4 % for the finer grained mate- rial. The % conversion to momentum is higher, increasing from 7 % to 11 % for the coarser grained material and 21 %