I have a .22 hw80 , tis a very good , accurate , well made air rifle if a tad heavy to carry for extended periods , I bought a pre charged .20 cal Benjamin pistol for ratting as my ratcatcher was overpenetrating and the rats were dying elsewhere(I needed tail's for proof) the .20 solved this particular problem and was a very hard hitting ratting pistol , ammunition choice/availability/price was a big problem I seldom managed to buy pellets of the shelf and more usually had to place online orders thus driving the price up....I would discount .20 on this alone, nut my choice in hindsight would be to go.177 for its flatter shooting as this is much more novice friendly with range estimation , if you feel the .177 lacks clout you can use the bisley magnums which are a similar weight in .177 cal to the average .22
should read but not nut