For $1200 you can have semi custom with GURANTEED .5 MOA accuracy.
If you just want a truck gun or plinker start with a stripped lower ($100) from RRA or Stag (they are identical and made in the same shop....all that differs is the rollmark). That is considered "the firearm" by the ATF. You go through your FFL and everything else for the gun can be ordered through the mail. Later just buy a kit for about $400-$500 and slap it together in about an hour. My Model 1 light weight CAR shoots under 1 MOA with 69gr SMK and Varget. I shot the first 1000 rounds without cleaning the bolt and carrier.....it never burped.
For a tack driver, get a complete RRA or Stag lower. You go get a stripped lower and the parts, but you don't save that much here. Then just pin on a quality upper. You can get a Clark Gator for $800 and still have money left for a Jewell trigger to make the $1200 mark. They are guaranteed .5 MOA with good ammo. You also get a chromed bolt, adjustable gas block, free float carbon fiber handguard.....
Or for a long range gun go with a White Oak upper. They have the 1:7 twist and have the same barrels (Compass Lake) that the 600 yard Highpower shooters use.
At that point you're only at $800......plenty left for good glass.