Go to
www.olyarms.com/usa.html and download their Adobe (pdf) catalog.
Check out page 27, the K6 and K8 uppers. I have an older version of the K6, mine does not have the picatinny rail gas block. This is the whole upper half, not just a barrel.
Oly's broach cut barrels are very good. The 1x8 twist will cover you for most of the good target bullets, 69 gr-77 gr, but is still accurate with 55 gr and 62 gr.
Get the Harris bipod option.
Plan on spending as much on the scope as you do the rest of the rifle.
I have the JP trigger and hammer, there are other popular triggers.
I have been through two previous sets of rings and scope mount rails, and just was not satisfied. I have settled on the Armalite scope mount, which is a one piece mount, rings and all on a well made rugged unit. You can get this mount in 1" and 30mm versions. It puts the scope centerline at the same height above the bore as the aperture on A2 carry handle sights. Also, it gives you enough forward offset to obtain correct eye relief.
Scopes, don't slap on a $50 Wallyworld special. You will end up spending nearly as much for a good scope as you did the rest of the rifle. I have a Leupold Vari-X III 6-20x.