Take a tennis ball and place it 30 yards away from your table setup where your scoped rifle is set up with sandbags or whatever.
Remove bolt and insert an empty deprimed case (without a lump of hankook tyre!) and use it as a diopter rear sight to place the tennis ball in the muzzle circle.
Adjust scope crosshairs to tennis ball centre.
That will get your shots "on paper at the range" and should save a few bullets.
And don't forget to bring your bolt!!!
BTW, you can also play with a
point blank range calculator, all you need is the height of the scope axis above bore axis, and the ammo details of course.