Depends on the rifle and load for me. Like the other day, with my 308win shot 150gr barnes triple XXX. Got 1.8" groups. Not good enough for that rifle. I like consistent better than 1.5". So I am going to play with it. But that gun shoots 165 gr sierra like no bodies businiess. But for that ultra light barrel, 1.5" is good enough. For my 10lb RUM, and 200gr matchkings, I expect .5" or less every time. For 180gr nosler partitions, I expect 1.1 or 1.2" groups.

Depends on use, want, gun, and load.