Just some random thoughts and observations. May be worth exactly what you paid for them, but>>>>

22 LRs are used an many a homicide. Looking at autopsy reports has been relieving. The wounded ones too, but the kills were what I looked at most times.
Their are really only 2 factors that come into play in most cases. Both of which relate to the bullet hole through the body
#1 is where it hits, and the angle it hits at.
#2 is a bullet that penetrates well. No 22 LR is super dependable for linear penetration and often veer off course, so the 1st factor is the most important.
Hits to the brain the spine and neck are instant in putting them on the ground. The closer the vertebra is the the surface the better the odds of hitting them.

Heart shots are usually fatal, but sometime they work instantly, and some times they kill over a period of a few minutes. Sometimes quite a few! If the ventricle supping the aorta is hit the man or animal usually drops instantly, or very soon after the hit.

The idea that a 22 LR is "totally ineffective" is untrue. Many many poachers use them and kill far too many animals with them but if a poacher makes a kill and the animal runs that poacher will usually let it go rather then risk exposing himself to being caught. I would never use a 22 LR for any reason other than a desperate one, but there is simply no reason for me. I have more powerful rifles and handguns and so I would use one of them. But I have seen the wounds made by 22s and I can say that they damage is similar to that done by some broad heads shot from bows. If the angle is right and the hit is well placed a 22 will kill most animals. Even the elephant has been killed with 22 LR now and then by men in the past, but to my mind that fact never made my CZ 22 an elephant rifle.

Accuracy becomes more and more important the farther down the power scale you go. I dare say you can't get very much below a 22 rim rifle, ------------ with any firearm.