Here is the data for various hammer spring preloads using JSB King 25.4 gr. pellets in the "full power" version of the AT44S-10 Long.... NOTE: pressures on the graph are in bar, not psi....
As you can see, increasing the preload from 2 turns out to 4 increased not only the power, but also the shot count by a couple.... going another 2 turns was a bit too much to achieve maximum shot count, but set up that way the rifle delivered 16 shots averaging 46.6 FPE at 0.97 FPE/CI, so backing it down just slightly should produce 2 clips (18 shots) at about 45 FPE with a 200 bar (2900 psi) fill and bump the efficiency to just over 1.00 FPE/CI....
One small glitch has surfaced, something I knew I would have to watch for from previous experience with a .22 cal AT44.... The hammer spring preload tends to back itself off as you fire the gun, so it will need either some loctite or a locking device on the screw to prevent that.... I'm thinking a hole in the screw with a plastic plug inserted to create friction will probably work....
Bob
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