To tell the truth I don't worry about .22 Magnum accuracy as much as I used to, because to me the .22 Magnum is a rimfire cartridge for bigger game than squirrels, whether tree squirrels or prairie dogs. If I want super accuracy for either head-shooting tree squirrels or zapping ground squirrels, I'll take a .22 Long Rifle or .17 HMR.
The .22 Magnum, it seems to me after 40+ years of shooting them, doesn't need to be as accurate, because it's best on animals weighing around 10 pounds or more, whether jackrabbits, foxes, woodchucks, or whatever. And super-accuracy isn't needed on those animals.
The .22 Magnum isn't as good a target round as the .22 Long Rifle, or as good a small varmint round as the .17 HMR, so why worry about whether it puts five shots into 1/2" at 50 yards? (Though I do own one such .22 Magnum at this moment, at least with one load.)
