If you can do the following, i will produce a scope label for you.
*Measure from barrel centre to centre of the scope in inches
*If i take your fps at an average of 780 fps (11.4ft lbs)
*What scope are you using? with what reticule
*I know from your pellet weight that you are either using jsb's or AA etc so thats fine
As above it will not be mm perfect but will be a solid starting point.
Theoben TTR1 .177, Steven B Blue/Grey Laminate Stock, Nutshot Mod, Falcon Menace 10x42 B20 Ret