Here is my opinion,....
Buy a complete 3gun rifle. Stag, Loki, Colt, Noveske, Etc. Then buy a Burris Mtac, mount and lots of practice ammo.
I.e. Stag 3G (1350), Benny hill comp (80), Burris Mtac (350), larue spre mount (220). Or Burris Pepr mount if funds are short (80)
Which is very close to your budget and will shoot lights out. This will be great as you get accustomed to it and get better, the rifle won't need improved.