mntmayfly

so i just picked up one if these used and i am having some issues. 1. when i fill it with propane for around 30 seconds i only get maybe 5-10 powerful shots if im lucky, the rest are very low power, maybe 20 feet max. do i need to fill it longer? 2. will this gun handle CO2? i have already went thru the gas block and checked for leaks, the o-rings that were leaking i changed out, no leaks now. thanks !