hi i recently bought a pmr and havent really had the chance to test it, the only thing i got to shoot it is an 20oz co2 bottle. Now i have heard from numerous people that co2 is bad for any gun but as i havent got an air tank i was wondering whether it would be ok to use just to test shoot a few paintballs through? Also can someone explain why it is bad for the guns and why it is available for use if it is?