No, its not easy at all.
I agree. If it were easy, everybody would be doing it.
Now this is where I like shooting at gongs. Take a - 6", 8", 10" gong, and so on and they all become one big bulls'eye, and you'd think a person could run the course of say (50 to 100 yards) with ease, (50 yards - 6",,, 60 yards - 6",,, 70 yards - 8",,, 80 yards - 8",,, 90 yards - 10",,, and 100 yards - 10",,, - but not so with fixed open iron sights. Now I'm not saying it can't be done but you'd better know your rifle well, and know your windage and elevation.
Here's the best run I ever did;
50y (6") - H H, 60y (6") - H H, 70y (8") - H H, 80y (8") -
M H, 90y (10") - H H, 100y (10") - H H