Just saw this thread and I happened to have just run about six boxes of different .22LR though my PC 15-22 in the past two days looking for the most consistent. Accuracy has as much to do with the shooter as the rifle. With that understanding I found the best groups for my gun was Eley 10X, SK Rifle Match, and Eley Subsonic HP. Again, this is bench shooting at 50 yards, finding what ammo keeps groups under an inch and these did. That said if you just want to run ammo and have fun plinking, CCI Standard velocity works great, but so too do many others-I'd stay away from the cheapest bulk stuff in an autoloader. What ever your intent, have fun.
Cheers!