Originally posted by dirtylittlesmurf
are you sure that tanks pressure is 3500? maby you mean 3000 or 4500? you are never better going with co2. for 3000 psi it is 10 shots per ci for 4500 it is 15 shots per ci. so you should get 480 shots off your tank. for 1200 you would need a 78/45.welcome to the world of high end guns, have fun.
Just remeber these are very general numbers. some guns are more efficient and some are much less efficient.
I get close to 2000 shots from a 68/4500 with my excal with my minimag I get more like a 1000 to 1200. Some of this is due to the fact that the excal has a much lower input pressure and this allows me to shoot it until the tank is almost empty.
If where you play it's free air fills this shouldn't be a problem. If you are playing renegade or outlaw you may want to stick with co2 for a while unless scuba tanks to refill are an option.