Up to what range are my .22 bullets still effective?

I have just bought a CZ .22lr rifle and I was wondering what the killing range of this gun would be and is it fit to kill a fox cleanly? I only ever shoot if there’s a safe backstop and I’m just looking at this in the worst case.

George Wallace advises. 

A: I will answer your questions briefly here and now.

Zeroed at 70-75 yards the .22 LR subsonic has a useful trajectory out to about 85-90 yards. After that it needs good judgment of distance and a good memory for the bullet drop at the range in question.

Ensure a safe backstop

The potential killing range is, of course, very much greater because the little bullet has more energy at 500 yards than an air rifle has at the muzzle, so you are right to ensure a safe backstop before every shot.

Opinions vary on shooting foxes with a .22 long rifle but the bottom line is that, with 100 foot/pounds of energy at the muzzle, it will most certainly kill a fox cleanly at short range provided circumstances allow precise bullet placement.

Rifle expert, Peter Frenette, tells me he has never managed to get a bullet from a .22 rimfire to go more then 800 yards.