Take a lesson with the NSSF and the Gunsite Academy and see how to use a short range zero for long range accuracy.
This is a great tutorial on one of the most efficient ways to get your rifle dialed in to make sure you are accurate at those longer ranges.
Some great tips to maximize your time on the range.
It is very common in the military to start the zero process at 25 yards. This allows a marksman to ensure he is on paper and make quick adjustments and as long as you are not way out at 25 you will be able to dial in the sight to zero in little time. Once on at 25 moving back to the 50 yard line and then 200 yards will allow for the finer adjustments and to build confidence you are hitting where you want.
These sighting in drills are great for your AR-15 but will work just as well with your favorite deer rifle or varmint shooter so is well worth trying out during your range practices.