On top of everything that has been said, did you try different kind of ammo. My personal rifle for example is extremely picky with ammo. So much so that if I just took random ammo I would not even bother shooting it. For a long time I thought it was just a "meh" rifle, until I hit the lots that it liked. And I went through a lot of ammo. That being said, every 22 rifle is different and it could be a lot of different things affecting accuracy.