Lotta PB and airsoft rigs have been made with 2 regulators. One at the bottle ine "mini" in line that often can be set from 0-600 or 800 or 1200psi depending on the regulator.
Runing external is still the best way to get consistancey and run it in cold tempratures.
As for using that co2 charger to run any gun/device by setting the proper psi.
Yes technically it should work but it wont really improve consistancy because the gas chamber is so small in a magazine itll be far lowwer pressure by the last shot.
Lotta guys use an adapter like that to run bb shower nades (40mm)
It technically should work for a tornado nade a pistol a gbbr or whatever you like so long as you dont exceed the strength of the device.
Folks use 800plus psi of co2 on 40mm nades. Ive heard of 280psi of HPA on a gas sniper rifle in a modified GG mag.
I think most folks use this co2 adapter
http://www.redwolfairsoft.com/redwol...O2_Adaptor.htm
And in order to use hpa your prety much stuck with and external setup for 2 reasons. 1 is the volume of gas isnt gonna be enough in a mag
2 is youll need the external setup anyhow and then somehow rig up that adapter to the end of it to fill your mags and such so u may as well just use the rig.