SpudFiles

What would happen if you used C02 for a pneumatic and pumped in more air?

I'm not exactly sure what you are talking about. Do you mean filling the pnumatic with Co2 then adding copressed air??

Ahhh Why? Why wouldn't you just add Co2 by itself? Co2 at 70F(I think) is at about 800psi. Unless your cannon is steel etc you will need a reg, So why would you reg the Co2 to say 40psi then pump it up to 60psi with a bike pump? Why not just reg it to 100psi in the first place.

Yeah, I really don't understand what he's trying to say.

You use Co2 for portability, and air is used for its cheapness. Using both is stupid because then its both unportable AND expensieve.

No, using both has its advantages, for the reason you already mentioned.
"air is used for its cheapness"
Conversely, CO2 is expensive. Lets say your cannon operates at 250psi, and your compressor only goes up to 125psi? It seems perfectly practical to me to supplement the compressed air with CO2 in order to get to 250psi in a more economical fashion.

And for all of you that are waiting to come back with "But you can buy a 250psi compressor for only $15!", I just want to point out that there are often times more than one way to skin a cat, and perhaps this person doesn't feel like waiting for a cheap compressor to fill up his chamber. He feels it is worth it to pay for the CO2 instead. To each his own.

No, to address the creator of this topic:
This is something I have planned to do in the past, but never got around to. It will work fine. You will also have a higher velocity than if CO2 alone was used. (Something else to consider before you call someone else stupid, Insomniac.)

I was trying to ask if there was any increase in velocity because of the mixture of gases, like how people can reach super sonic if they use helium for a pneumatic

Your velocity will be better than CO2 alone, but lower than air alone (at the same pressures.)

The idea is, the lighter the gas, the higher the potential velocity.