I have a similar setup.
16" SS 1:9 barrel shoots 1/4 MOA. (When I do my part)
Chamber in mine is tight. Shoot domestic ammo only.
Black Hills 68 moly-hollow produces best results. (~$25/box of 50)
Mine requires "red box" (reman "blue box" out of spec)
Use XM193 inside 200 yds. (More trigger time / less money)
Still shoots dime groups at 200 yds after 2000 rounds w/ BH68.
Break in barrel with JB bore paste, Kroil, Militec, & a Dewey cleaning rod.
Get a "railed" gas block if you want to shoot BUIS.
Chromed carrier is a good idea. (Bolt too)
Invest in a good trigger. (Jard works great for me)
Get a 20" if you want to shoot groundhogs beyond 500 yds.
16" suits me just fine.