Transverse-momentum and angular distributions of all residual charges due to fragmentations for 16O projectile on emulsion at 3.7A GeV are recorded and compared with that obtained for 12C, 22Ne, 24Mg and 28Si at the same momentum. The experimental parameters that indicate the mechanism responsible for projectile fragmentation are discussed. The effect of target size on fragmentation process for both 16O and 24Mg projectiles are studied. The results, in the given range of masses and energy show that there is unified mechanism responsible for projectile fragmentation.