Well... Up until I decided that I actually *wanted* to see the little buggers explode into a red mist, (After I ran the figures of just *what* they were costing me from damaged crops, damaged land, loss of pasture rental because of possible injury, and a few other `goodies'! [And the *average* figures over a 4 year period were *only?* $17,000!]), I was shooting Prairie Dogs AKA `Pasture Poodles' at a *measured* 185yds using a scoped, 4-12 X 32, beat up old Winchester bolt action .22. That was doing it *reliably*! I was doing it a bit less than that further on out. {FROWN!} 'Course I *did* always `take advantage' of `available support' whenever I could, too. Once it gets past about 55 - 65 yards I'm just too danged shaky for something that small with *that* small of a `boiler room'.
As for 800yds using a 40gr .22lr!? Yikes! Those things must be moving slow enough to run alongside and make mid-course corrections!? {GRIN!} And as for the energy??? I *do* know that .22s aren't anything to be `trifled with' but... I just can't see anything but a *PERFECTLY* placed shot doing much more than just `getting their attention' the way a pea sized spitwad would after going across a football field. I know that my `reliable' shots at 185yds usually required a follow up for the `coup-de-gras' quite often. That's why my `other' .22s are either .222 or .223 these days. (The .222 w/ 40gr Nosler B-Tips gives the little buggers `reversible fur coats'! {CHORTLE!} And the eagles, hawks, and coyottes don't have to hassle with the hide{s} for a quick snack.)