What you will need is an ASA fill adapter rated to handle unregulated 4500 psi. There are a few options out there. I had to learn this stuff the hard way which was costly but I finally ending with a workable system. Most of this stuff is for the Paintball industry to be used with their paintball markers but can be adapted to be used with HPA/PCP guns also.
First option is the least expensive but also has the greatest downside to using it.
Ninja 4500psi Fill station with bleed valve This valve setup will do the job and do it quickly but can also damage your gun if you're not careful to watch the fill pressure closely. Then shut it off quick before it over pressurize your gun to 4500 psi. I learned this the very hard and costly way. This type of ASA bonnet valve screws on top of the threaded ASA regulator that is install on the bottle.
Next option cost more but is what I ended up going with in the end after all my experimenting and has worked wonders for me in the field.
Ninja EZ slow fill Valve system this valve system allows you to slowly fill your gun to the recommended psi and then keep turning the valve to the off position and it automatically bleeds the pressure from the fill line. With this system you have to remove the old ASA threaded regulator valve from you bottle and install this new Ninja EZ valve. There are Ytube vids that cover the install and usage of this valve.
Last is the most expensive option and it's an All In One package. It has the Ninja EZ valve already installed on a small 90ci bottle.
Ninja EZ valve and 90ci bottle Combo Package Well I hope this helps and keeps you out in the field longer enjoying your outing and your gun!
