Does a CO2, or other form of air-fed pistol or rifle's accuracy / velocity decrease as the CO2 cartridge becomes depleted? I ask this question because I would like to buy an air pistol for backyard shooting and I am not sure if I want a spring gun / CO2 powered / or a pump type. I'm looking for the best trigger-pull and something that is consistant in accuracy / velocity. Thanks, -Craig Wanna kill these ads? We can help!