Have you shot rats.? .[/QUOTE
I have and do ... from an upstairs window it's about 40 feet to the bird table and I get them when they can't resist the seed we put out for the birds - being higher than them they don't seem to spook as easily as when you are at ground level and the few seconds they are still when feeding is enough for a shot. I have a Weirhauch HW77 springer with an upgraded (but still legal) spring and piston assembly and a Tasco scope - I use H&N Barracuda extreme which drops them like a stone (they are supposed to be longer range than 40' but the kill at this range is usually pretty near instant, they sometimes twitch for a second or few but I can live with that). The underlever action means you don't have enough time for a second shot but I've only had one that limped off very slowly and the second shot finished it quickly. I don't like killing things but rats are an exception. The ones I get are relatively small - I don't know how my .177 would deal with some of the 18" monsters you seen on you tube hunting vids ...
I'd love an HW100 PCP but at £800 it's out of my budget for killing a few rats. I have been thinking of making one of these as I'm pretty sure there are a few that only come out at night - it's not as pretty as the real thing but at a fraction of the cost worth a try.
https://www.youtube.com/watch?v=sg5-z_RXQp0
There's a few variations on the theme - but mostly use the same bits off Amazon or ebay and the only difference is how you mount in on the scope.