Hello everyone. My friend want's to sell me his 'King Arms Colt M4A1 GBBR' very cheap.. Here is a link: http://www.kingarms.com/productpage.asp?prodid=1889 So i thought about converting it to HPA. My question is: Can i just buy a tank, regulator, hose and a quick connector to screw into the mag.. And that's it? Hopefully you guys can tell me more about this, because i don't know ANYTHING about HPA.. Please post some parts and tell me what i need to convert Thank you guys!