Originally Posted by haynboy8223
It all depends on the gun and if the guys at Dicks sporting goods filled it to the max. That's why I always fill my tanks at a paintball store for optimal amount of air.
One other thing the weather out side could also be a cause of this. Good luck.
Originally Posted by Milky Spore
there's a certain trick to filling a co2 tank properly. the guy at the dicks sporting goods store probably doesn't know jack **** about how to fill a tank either and is doing it wrong. i'd go to a paintball shop if you have one near you. if not, maybe request a new fill station tech be put in place of the old guy.
CO2 is gauged via weight, if it wasn't all the way full, it wouldn't weigh 20oz provided the person recalibrated the scale to account for the empty bottle.
However, what most likely happened:
CO2, when going from a liquid to a gas, is an endothermic reaction, or it requires heat. In a perfect world, expanding CO2 will put out about 800psi if it gets enough heat. However, in 60* weather after 300-400 shots, the tank will be so cold and the outside won't be hot enough to heat it fast enough, will result in two things:
1. the output pressure would lower more and more until it dropped below the threshold that the tippman and spyder needs to properly cycle.
2. It would be putting out a lot of liquid which wouldn't expand until it got enough heat to fuel that reaction.
The CO2 will expand at a force of ~800psi max, so the gun will shoot at the same speed(assuming it was chrono'd at 800psi) even though it is pouring useless liquid out of the barrel(useless in the fact that it isn't being used to actually fire the paintball). It will also be operating the gun below ~400-600psi needed to actually fully cycle a blowback.
Combine that with the 16 year old not fully filling the CO2 because he forgot to press "tare" on the scale then and I think that is the series of reasons why you only got 300 shots from a 20oz.