At 600 yards the M1A will get the same MOA as the mini30 at 100 yards.
Now let's not get carried away. The Mini 30 Tactical was reviewed right here on this website. The author was able to get sub inch groups at 100 yards with several loads. Sure, there are higher end customized M1A type rifles that can be shot accurately at much longer range than the Mini 30. But not anywhere near the level of difference as your example.