What are the advantages of using a co2 tank over an air tank

[gunslinger124]

Ive been designing an automatic co2/ air rifle. I have seen several on here that use co2 tanks instead of a tank of compressed air. Why? Is it because you can achieve a higher psi with a smaller tank? Does the co2 last longer without going empty? If I made an automatic co2 rifle, could I just substitute the co2 tank with an air tank without it affecting the function and reliability of the gun? Sorry for a question with a slightly obvious answer, I am just somewhat new. lol. Thank you all very much.

[flashskate13]

Personally I think HPA is better than CO2, HPA is less affected by temperature.
Plus if your short on money you can fill them at home easier.

[gunslinger124]

yes, i am trying to make a big bore auto airgun for survival purposes or something like that. I would prefer air powered because I could just cast my own bullets and fill it up with an air tank myself.

[flashskate13]

Well if its for survival purpose I would be thinking how I could fill it on the go!! And I would say HPA would be better as you will be able to do so. And a stirrup pump for a PCP air rifle will do the job. My old armed forces backpack holds my PCP air rifle one side and pump on the other. And I done some treks with it.

[cammyd32]

C02 is liquefied into capsules, what this essentially means is that you can have a larger volume of the stuff stored in a smaller volume, also it is easier to achieve higher pressures at a more consistent pressure as the vapor pressure is constant as long as there is still liquid co2 in the system, pcp's will have a vastly improved consistency because of this. (as long as you don't shoot fast enough to not allow the co2 to warm up between shots)
Hence why people use it as opposed to HPA, as you can get more shots out of a little 12g cylinder than one massive paintball tank charged to pressures of (insert big number here) psi, if you really want to go in depth with it have a look here
But short version is:
more shots smaller volume

[jackssmirkingrevenge]

Co2 is a denser gas and therefore for a given volume of gas at a given pressure, it will give lower performance than air.