Bill,

I fitted a 0.22" Wonky Donky service kit into my 0.177" HW99S, and it made ca. 10.0 ft.lb, with no compression washers fitted.

Lovely to shoot, and much easier to cock that when the rifle is at ca. 11 ft.lb.

Compare the trajectories of 10 ft.lb, and 11.5 ft.lb in Chairgun, and you see you are losing virtually no trajectory with 10 ft.lb

Have fun

Best regards

Russ