Abstract: A paintball gun that operates entirely under a single stage of gas pressure and uses fewer parts thereby resulting in lower manufacturing costs and higher reliability without any significant impact on its firing sequence rate. The paintball gun employs a mechanical spring to reset the ram. Resetting of the ram by a mechanical spring being returned to a less compressed condition, does not appear to have any significant effect on firing and reloading sequence rates as compared to resetting the ram with pneumatic operation. Employing a mechanical spring to reset the ram, reduces the complexity of the pneumatic valve. The less complex pneumatic valve can readily operate under higher gas pressure such as up to 300 psig thereby making it unnecessary to have a second stage of pressure.