If your budget is firm at $600, then the X-bolt and Tikka are both over your stated budget. Remembering that you still have to pay for a scope and mounts for them too.
The other option is to see what you can buy in terms of used. There are some great deals to be had out there. Check on the EE as well.
The third option is to then begin to look for a rifle within your budget range.
The Ruger American, Savage, Axis, Remington are other options as well. I would also suggest my personal favorite of looking at the Weatherby S2.