I have a used Browning X-Bolt that was previously owned, but never shot in .30-06. It is by far the best overall hunting rifle I have.
So, I have the proceeds from a few guns that I sold recently, that I am rolling into another X-Bolt in .243.
The X-Bolt is an extremely accurate rifle, and my 30-06 has a very tight chamber, allowing me neck size only me brass, and have minimal case expansion, allowing for more accurate shooting and minimal brass stress. The 30-06 shoots all factory ammo I tried 1.25" or less at 100 yards, and I have multiple handloads that cloverleaf.
The .30-06 is topped with a Leopold VX-III 3-9, and for the .243 I have a Leopold VX-II 3-9 sitting on the bench for.
I hope the .243 performs as well as the '06.