I have a Logun Solo (FX Typhoon) in .177 running at 11.4 ft'lbs. It is fitted with a Ben Taylor & Son regulator and has always been remarkably consistent and economical on air, giving 100+ full-power shots over the last 5 years or so (over 20,000 pellets).
A problem has arisen whereby the first shot after the gun has been left overnight is down to about 8 ft/lbs (around 660 fps). The next 3 or 4 shots show an increase in power so that by the 4th or 5th shot the gun has attained the full 11.4 ft/lbs again. It will then remain on full power during a normal day's shooting. This problem still occurs whether the cylinder has the full 230 bar (recommended by Ben) or has run down to 100 bar or so.
I've replaced all O-rings and seals (except inside the regulator) and cannot detect any air leaks, so I am at a loss as to what might be causing this problem. Ben Taylor has retired now so I can't get it serviced by him. Does anyone have any ideas on what might be causing this problem? Any help would be greatly appreciated.