The most accurate rifle I have is a Sako L691 (circa 1994) in 300 WBY. On a bad day I'll shoot a 3/4" group (3 shots) at 100 yards. On a good day, those groups will shrink significantly.

With that said, my son and I have Marlin 336s (circa 1971) that I can get a little over 1/2" groups with at 100 yards (3 shot) with Hornady Leverevolution ammo.