If one were to ask a skilled 3 gun competitor the same regarding 6x magnification, with shots ranging from muzzle to 450-500 yards, they'd tell you that 6x is plenty to hit the average target which is 8-12 inches.
All I know is, I have no trouble centering the crosshairs of a 6X on a 12" target at 550 and hitting it. And I'm not what you'd call a highly-skilled marksman.
My wife, daughter, college buddies of my son, my 79yr old father that hasn't shot a rifle in 10years, etc., don't have any problem hitting 12" steel at 500yds w/ 6x - in a lightweight rifle - even from prone off a backpack (except my dad, he wasn't laying down to shoot...)
