Different pressure of N2 and CO2?

[ShawnD1]

I'm going to go paintballing in the near future and I'm wondering whether I should use the nitrogen powered guns or the carbon dioxide powered guns. The nitrogen powered ones cost more to rent.
Do nitrogen and carbon dioxide have different work functions for compressing them? Does it take more energy to compress nitrogen and less energy to compress carbon dioxide?
Does the difference in gas actually change the performance of the gun?

[Blazer06]

don't know just bought my gun, haven't even used it yet. I wernt with co2 because it costs less than nitrogen. easier to use, for newbies.


Blaze

[Chuckiechan]

CO2 loses velocity when you shoot fast, so your balls drop. We can't have that, can we!

Nitrogen shoots straighter because the pressure climbs back to 100% more quickly.

[zskillz]

Originally posted by Chuckiechan
CO2 loses velocity when you shoot fast, so your balls drop. We can't have that, can we!

Nitrogen shoots straighter because the pressure climbs back to 100% more quickly.

think you could explain this a bit more. Now I'm no stranger to the workings of pressure, but I cannot make sense of what you are saying...

thanks

-Z

[Pepete]

simple, the Co2 is heavier so it takes some more time to expand in the gun/valve assembly and might as well freeze when you shoot very fast because it won't have time to expand at all (especially if you don't have any expansion chamber)

[vass0922]

In English...

(these are not exact numbers just numbers for arguments sake)
CO2 shooting fast
Ball 1 = 60mph
Ball 2 = 55mph
ball 3 = 50 mph
ball 4 = 45 mph... and downhill

NO2 shooting fast
Ball 1 = 60mph
Ball 2 = 60mph
Ball 3 = 58mph
Ball 4 = 58mph

As you can see the NO2 does not lose velocity nearly as fast as the CO2 as you shoot rapidly. Theoretically with CO2 by the 10th shot your paintball would fall out of the chamber instead of shooting while the guy with NO2 is going to be laughing his butt off pegging you with 10 shots while you're waiting for pressure to recharge

[ShawnD1]

Ok let me see if I understand. The gas expands quickly not only due to the difference in pressure but the difference in temperature (ideal gas law). When CO2 expands, it cools the chamber significantly to make the next shot expand much slower. With NO2, the expansion of the gas does not change the temperature of the chamber as much which makes the next shot expand almost the same speed.

Sound about right?

[Theophylact]

No, I don't think that's the reason. The problem is that the CO2 is mostly liquefied. As you bleed off gas, it's replaced by some of the liquid boiling off. But that phase change requires a lot of heat; the remaining CO2 is rapidly cooled, and as the temperature drops, so does the pressure. It takes time to reequilibrate, by picking up heat from outside the cylinder; until then, the pressure is low.

With N2, you're far above the critical temperature; there's no liquid in the tank, just gas at high pressure (much higher than that in a CO2 tank). As you bleed off gas, the pressure in the tank drops; but you've got a controller valve allowing gas out at a constant pressure (until the pressure in the tank falls too low).

[Chuckiechan]

And...

Atmospheric air is the preferred choice...Using scuba tanks.

I'm not sure why, but it never fails to amaze me as to the knowledge available on this board!