Bob,
Thanks for the info.
As noted in my original post, I've owned a bunch of .22 Magnums and all except this Ruger were very ammo-sensitive, even more than the average .22 Long Rifle. Haven't checked my records but can't remember one that wouldn't scatter at least one load like your rifle scatters the CCI 30-grain stuff.
This was fine back when .22 Magnum ammo of various kinds was easily available, but that's not true today, I suspect because so much production time is going into making .17 HMR ammo.
Plus, .17 HMR rifles of all brands seem to be accurate and remarkably ammo insensitive. It's rare for .17 HMR ammo of any kind to average groups over an inch at 100 yards--and they all seem to land in close to the same place. I tried four different kinds of .17 HMR ammo the other day in my CZ. The four 5-shot groups averaged under an inch, and all 20 rounds went into 1.63".
