Just a guess, based on a sample of one Ruger American, but I suspect that current ammunition isn’t quite as good as it was when the little round was introduced. That could have changed, or not, but I’ be interested in how your rifle does as well.
My Ruger American in 17HM2, from the non-cataloged run that SAS had made, is the least accurate 17HM2 rifle that I've owned. I might have got a dud, but even the least expensive Savage Mark IIs shoot better groups. Very disappointing.