With co2 you learn as you go along. Don't worry about it, everyone uses it for rec-ball and most have at least two or three bottles, to change over with.
When you shoot pretty fast and prolonged strings of balls, the demand put on the co2, chills the bottle down and causes the pressure to drop in the bottle. Obviously this is more pronounced in the winter as the weather is colder. The bottle takes a while to get back to a normal operating temp, and recover a bit. For example, on an old shocker i shot a hopper full of balls, more or less continously, and the bottle had a white sheen on it, the pressure had dropped considerably, and i had to change that bottle at the end of the game.
This is why compressed air is so popular, you don't get these problems, but bit expensive for the average rec-baller.
Enjoy your paintball, and if there's anything you don't fully understand, please ask, that's what we're hear for.
Tom.
