Yes 17hmr is RUBBISH for fox, I had one for 2 years and although I only shot 2 foxes with it, had to shoot both of them at least twice, (I have two centrefires so never set out to shoot a fox with the 17)
That said who's watching when you are out and about? Also neither fox made it to fight another day.
I've also shot loads of foxes with a .22 rimfire, to be honest at close range (less than 75 yards) the .22 performed better than the 17.
Anyway a centrefire .22 is the lowest rung for foxes in my opinion, and it seems in most police authority areas as well.
AndyF
My 17hmr put a hole