I recently purchased the Huma-Air Tuning Regulator as well as the bottle adapter so I can run a larger bottle with M18X1.5 threads. I picked up a 480cc used Daystate bottle and the max fill pressure is 250 bar not 300bar. I double and triple checked that I installed the Huma-Air regulator correctly. At first I hadn't looked up the fitment instruction but after doing so it fixed the leak buy adding the oring that it did not come with but is on the stem of the AGT reg. I had my factory reg turned up, as well as a little cheat for a heavier Hammer spring by preloading the spring with the appropriate sized washers. Went from shooting light weight and I mean very light weight .22 pellets too. After making those adjustments to the stock regulator and the hammer spring I was easily shooting the .22cal 22gr XL-HP Varmint knockers easily over 1000fps. But there is a price for that high power tune. The Vixen does have a 300bar fill, however I believe the CF bottle is only 200cc. So you're just using up air so incredibly fast, and I'm maybe a month away from buying a compressor that will fill my bottles. So I went ahead and purchased the Huma-Air Tuning Regulator for the Vixen as well as the bottle adapter which allows you to put any bottle on that has the standard M18X1.5 Threads. I replaced all of the orings I could manage to find in the area where the bottle connects to the gun and throughout the part that holds the regulator. The Huma-Air regulator will not work in my Huma-Air regulator tester, not sure if it's a size thing or if I can't test Regulators that small. Before doing any of this the gun was shooting 1000fps plus no problem. Now it's twice if not 3 times as loud, went from 1000fps to 700fps. There is a small hole under the regulator housing. That's where it was originally leaking air from before I added the oring to the stem of the regulator. I have to completely de gas the gun each time I make an adjustment, which wouldn't be much trouble if I had a compressor already. Couldn't tell if perhaps I had turned up the Huma reg too high and the hammer wasn't smacking the value with enough force so I turned it down from 160 to 145 and the issue remained, fps dropped to 600 and it was still very loud. Mine is set up as a left handed cocking. My AGT Uragan King in .30cal is left handed as well as my RTI P3 .22CAL. Anyhow, the Vixen is not a Bullpup like the rest of my PCP'S and the cocking lever is next to the magazine well. I can feel a rather large amount of air coming out of where the magazine slots in. It never did that before. Lastly to make sure it wasn't the huma regulator I installed my stock AGT regulator in there and tested it again and it did the same exact thing. Also it was leaking from the small hole in bottom of the part which houses the regulator but it was extremely slow. I am running out of any solutions, I love my AGT Vixen and I would greatly appreciate any helpful input or suggestions. I appologise for the super long story and greatly appreciate those of you who took the time to read this monster lol. You can email me personally as [email protected] or feel free to call or text me at 480-823-2732. Thank you so very much! Looking forward to hearing from you guys!