Question about C02 vs. HPA rig for KJW M700
 

How much psi from an air compressor do you need for an HPA tank?
Does the CO2 rig lose fps every shot, like in the cheap CO2 pistols?
Does the CO2 rig have adjustable velocity? Like the HPA.
Is either more accurate or more consistent?
Hopefully someone with experience with either set up can help. Thanks.

Although I have never done it with a KJW M700, I do use an external HPA rig for my G&P WA M4.

Typically most air compressors won't fill an HPA tank (Not much past 100 or so psi anyways) They simply don't put out the pressure required to fill it past that point. (Most HPA tanks are 3000-4500psi now)

With an external tank the pressure drop is only a problem with very fast consecutive shots. The drop in pressure will be partially determined by your setup, personally I use a second regulator after my palmers regulator to help reduce pressure drops when going full auto with my m4. Also having lots of extra tubing or a coil tube in between the regulators acts as an expansion chamber.. lots of people that build there own HPA rigs don't leave enough tubing and they will have greater pressure drops with the palmers trying to keep up with the 2nd regulator.

AFAIK you can use either C02 tanks or HPA tanks with palmers based external air rigs.. just get whatever is easier to obtain.

This is something I'm not too sure about.. Here's a debate over GreenGas(propane) vs c02:Re: Why aren't most GBB's C02? Is green gas/propane better?

Here's some links:

WTS: Pre-assembled dual-reg gas rigs

Air Rigs Parts List

Air Rig Planning Ahead

That GBB lover guy is a f'n tool. There should be an Intellectual Trauma warning next to that link :(

So with C02 and a bolt action rifle, I shouldn't expect an fps decline?

If your talking about an external rig of CO2, then you shouldn't notice a difference between CO2 and HPA except effeciency of shoots per tank. External rig always require a regulator, the fps is as consistent as the regulator.

Ok thanks acer I get it.