The rifle, bullet, and shooter will all hold 1/2 moa.
The ballistics get really interesting at one mile. That 1/2 moa is almost 9 inches at the target at one mile.
Misreading wind by one mph at the firing line will move the bullet almost 15 inches. And of course, wind counts at the firing line, over that canyon, fifty feet in the air, and all the way to the target. The bullet is in the air for over 2.5 seconds. We have tell-tales every 200 yards and have seen wind blowing in one direction at 600 yards and the opposite direction at 1600. This was a relatively calm day.
Much of what we teach is how to use the reticle at long range in addition to making sure everyone understands external ballistics, and the effect of distance, wind, angle shooting, spin drift, and most complex of all, the Coriolis effect. The latter is real, but only significant at these kinds of distances.
Come join us. This will be a blast.