I have a RWS 34 in 177. I bought an el cheapo(just bought a house not much fundage available for a while) airgun scope made by daisy for it. When I mounted it and fired it the first time it struck low. Well adjusting it I finally ran out of adjustment. Well I tried a shim of electricians tape under the scope in the rear ring. I didn't tighten this down tightly for fear of breaking something. Well it has more than enough adjustment now for 10 yards. However at 25 yards it strikes pretty high still. Do these airguns have a strange trajectory that would explain this or is there something I am missing? If I were to remove the tape would this maybe impact normally at 25 yards or so? I don't even know the nominal range of these airguns. Somebody lend me some information here.

"Liberty is never unalienable; it must be redeemed regularly with the blood of patriots or it always vanishes."
"That the timid are not philosophically qualified to comment on the activities of the courageous." Jeff Cooper