I bought a stainless Mini 30 about three years ago, and have found it favors certain ammo over others for accuracy. With surplus, steel case Tula ammo, if has "Ho-Hum" accuracy, probably 6-8" or so at 100 yards with iron sights. With factory brass case ammo such as Winchester White Box, Federal FMJ or Fiocchi, 3-4" at 100 yards, The most accurate is PPU Soft Point Round Nose, 2" at 100 yards. When I found the rifle favored PPU Soft Point I bought up all I could find, probably got 800 rounds or so of it salted back.
Here's a pic of hits on a steel rabbit, PPU Soft Point Round Nose, fired from the prone position at 100 yards: