When switching air sources on a gun or rather switching from Co2 to Compressed Air on a gun you should always re-chrono and whatnot. You should almost always need to up or lower the reg/velocity since Co2 and Compressed Air are totally different.
When it leaks down the barrel when you first air it up, thats normal. You must cock the gun before putting air to it. I will say USUALLY as I do not have to do this on my S6. Its just fine when I first put air to it.
__________________ - VIGILANTE/3rd Eye Vision - - AOP - "Support the art that supports you!" - CCM - "The BEST....made here in the USA!" - I&I Sports - "Cant find it? Did you check here?" MY FEEDBACK