Be careful about the jdsairman website. The guy make statements that are not accurate.
I've been a paintball player for years. I own/have owned multiple makes/models of PB guns as well as worked on other's guns. Jdairman claims paintball guns have an internal regulator that drops the pressure down to 400psi for the gun to use. That is entirely untrue, except possibly in the obscure Autococker, where it MAY have a regulator to operate an air cylinder that cycles the bolt. Paintball guns use either "HI" pressure (800-850psi) or "LOW" pressure (400-450psi) to operate. Spyder and Tippmann designs use the higher, 800-850psi, pressures to work as excess gas is used to blow the action back and load a new ball. Many of the newer guns use the lower pressure because it is quieter, uses more of the tank and is easier on the ball (more accurate?).
Claims of a PB regulator not working with an AR is not true. Air is air, pressure is pressure and a projectile is a projectile.