Ah the old debate on FAC air rifles-regulated or fast flow? My own take on this is quite simple. For a start you do not NEED 40 ft lb. Even using the 21.4 grain Baracuda/Bisley Magnum (which are pretty heavy but probably the best pellet for high power air) I ask anyone to tell me what a 40 ft lb rifle can do that a 30 ft lb rifle can't do other than waste a lot of air!! I have run my Rapid at most power levels and after a lot of mucking about and wasted air I run my current gun-a Rapid 2 with 19" 'Leupy' barrel in .22 at 30 ft lb with a Theoben MFR regulator set to 125BAR working pressure. No power curve, very smooth power delivery and a respectable 4 magazines (48 shots) from the (smaller)280cc bottle filled to 220 BAR. The only rifle that I liked more for FAC .22 air is the Edgun Matador R3 which delivered 40 shots at 40 ft lb with a 200BAR fill which went 'off the reg' at 100BAR. That to anyone who understands regulators is truly PHENOMENAL efficiency! Sadly the Edgun has magazines that stuck in my face as a left handed shooter so I sold it. If the magazines could go in either side of the breech so they didn't stick out so far on the right of the gun I would not have sold it. The Air Ranger is a good gun and frankly if it were mine I would reduce the power to 30 ft lb and stick with the simplicity of the fast flow that you have on the gun already.
'It may be that your sole purpose in life is to serve as a warning to others'.