1. In the decade or so that I've been here, it's been extremely rare to see a 1:10 twist barrel to perform well below the 168gr bullet weight. Go heavier with your bullets.
2. GIGO - Garbage in, garbage out. Match ammo is going to be the best indicator of your true accuracy potential.
3. If you aren't confident in your gear, your fundamentals will tend to be executed poorly. Get an optic and rings combination that's unimpeachable in quality, this eliminates your kit as the weak link and leaves you with a much clearer idea of the accuracy potential of you and your rifle combined.
4. A 3-shot group won't tell you very much about how accurate your rifle is, I'd shoot at least 5-shot groups, if not 10-shot groups.