No, they are not.
Assuming your rifle is a bolt-action, simply remove the bolt, put the rifle in a rest or on a cardboard box with a V cut in it, look down the barrel from the bolt end at some distant object, farther is better, and then adjust the scope so the crosshairs are on what you see. Keep in mind that the crosshairs move the opposite of the direction you might normally expect when you turn the dial.
That's it. You should easily be on paper at 50 yards, 100 if you do it right, especially with a tiny bore like the 17.