10/22 accuracy
You haven't mentioned that you've tried any different brands of bullets.
The accuracy you're getting is very poor for 25 yards from a 10/22, even for grouse, unless you're trying to scare them instead of hit them. At most, that group should be 2" in size.
If you haven't done it already, I suggest getting some different brands and test them out. If you have done the testing and this is the "best", then there is something wrong with your setup.