In this paper the performance of a single stage capacitor driven coil gun electromagnetic launcher (EML) is investigated. The driving coil of the launcher creates a current pulse that depends on the capacitor charging circuitry specifics. The coil gun electromagnetic launcher system is analyzed using a mechanical model coupled to a magnetic finite element analysis model. The effects of changing the capacitor voltage level and the initial position of the projectile on the acceleration, speed and force are examined. The proposed analytical tool provides accurate calculations. The relations between the capacitor initial voltage, the initial projectile displacement and the final steady-state projectile velocity were examined. It was found that there is an optimum initial position for a projectile to achieve maximum launch velocity and this position depends on the projectile dimensions, mass and the value of the capacitor initial voltage.