CO2 Vs Gas Hi Capa Mag 

What up grade you did to the hicapa to make it co2 compatible, will you need to upgrade the valve knocker and other internal of the frame as well?

There are a couple issues that could be at fault here, 1. Your green gas was extremely warm 2. Your CO2 Mag is not releasing as much CO2 as it should be when firing the gun. It is a fact that CO2 has a higher pressure output than airsoft "greengas" or propane which are the exact same thing, mind you "greengas" has silicon oil mixed in it and is odorless.

Its what it is matey. The CO2 is less. I dont know how.

I dont get it I have this mag and for the life of me cannot get the bottom off to put c02 in anyone have this problem?

thas not right, unless it was hot

Your gun is very weak man . Its realistic looks is useless if your gun is not that strong