Alycidon,
Here in Montana we mainly shoot prairie dogs, with rabbits, skunks, porcupines, and coyotes being the other major varmints. Of course, eagles carry off lambs, but they are not "legal" to shoot, being the national bird and all that....
Some Montana sheep ranchers seem to be short sighted, though.....
The smart eagles stick to grabbing fish out of the river.
However, I have a Hawke 3-12x50 Nite-Eye scope with SR6 ballistic reticle and a Bushnell 1000 Scout rangefinder. I used the Hawke ballistic program to set up my scope relative to the two pellets (.25 H&N Baracuda and .25 JSB Exact King) that I use. Drop at range out to 100 yards is not a problem, the limiting factor being wind, as this is the Montana prairie. The kind of wind you have to lean way back in order to stand up at times.
An ex-police sniper looked at my groups at the 100 yard shooting range and said, "That would be really good for a centerfire sniper rifle".
Enough said.
BTW, I use a BSA Lonestar .25 as my chosen air rifle, so as a Brit, you should be proud.