Paintball Tanks
There are two types of propellant tanks which are used in paintball; Carbon dioxide and nitrogen or high pressure air. Carbon dioxide tanks utilize liquid carbon dioxide which expands and propels the paintballs into the barrel. This kind of tank however leads to the formation of ice crystals with time while the liquid changes into a gaseous state.
When used for a long time, they can become unreliable and their accuracy goes down. Nitrogen tanks on the other hand do not undergo any gaseous exchange like the carbon dioxide. This augments on the accuracy and distance unlike the former. These tanks are however quite heavy and expensive.