Help on air rifle scopes!?

A redfield 3-9 by 50 is most likely a firearm scope. it should be fine. If it was a 10 dollar one from walmart no, but its a redfield and if it was made for a firearm it can certainly withstand the jarring recoil of a spring gun. It should be fine to mount it on the gun. There is no way for them to prove you misused the scope by using it on a spring gun so it your warranty should still apply.