Knowing how to properly zero your rifle will save you both time and ammunition, not to mention ensure you hit your desired target. Using an improperly sighted firearm can be an extremely frustrating situation. There are a lot of ways out there thought to be the best practice when zeroing your AR 15 rifle, but today we are going to discuss how to zero an AR 15 rifle at 50 yards. Why at 50 yards you ask? If you zero at 50 yards, you also zero at 200 yards. This is possible because of the bullet’s trajectory.
Understanding Bullet Drop
Gravity is a great thing that keeps us all from floating away, but it also plays a key role in shooting. We have all heard the old saying that what goes up must come down, and it holds true for firing a bullet. When the bullet exits the barrel, it is traveling very fast through the air and losing elevation the more distance it travels. This needs to be taken into consideration when zeroing your rifle. Point of aim (POA) refers to the straight site line from a shooter’s eye to the target. During the course of a traveling bullet, the bullet will travel slightly above and below the POA depending on the distance. When zeroing, point of aim needs to equal point of impact (POI). Look at the diagram below, the rifle is shown at the left with the dotted line indicating the point of aim, and the solid line indicating the bullet trajectory. At 50 yards, the point of aim is equal to the point of impact, and because of the way the bullet travels the point of aim is equal to the point of impact at 200 (shown on diagram at 225) yards as well. This zero setting puts you on target at 50 yards, 1.6 inches high at 100 yards and back on target at 200 yards.
Zeroing Your Rifle
First, set up a target at 50 yards away. Then set up a solid rest for your rifle to be well supported using sandbags, or a bipod.
Getting the rifle on paper:
Next, get your rifle on paper, meaning get some shots on paper so you can look at the grouping. Get your barrel and scope in rough alignment and shoot 3-5 rounds at the bullseye so you have a grouping (should be fairly close together) to adjust by. If the grouping is not tight together, determine the cause (possibly flinching) and make corrections before moving on.
Adjusting a Scope: Adjust the cross-hairs in the direction you want the bullet to go as indicated on the scope. For example, if you are shooting low and right, turn the screws up and left the appropriate clicks. Remember the scope will usually be marked by a per-click graduation such as 1/4 inch per click at 100 yards, so for 50 yards this would make it 1/8 inch etc. Adjust by estimating the distance you are off by.
Adjusting Sites: To Adjust the sites, move the rear sight in the direction you want the bullet to go. For example if you are shooting high and to the right, lower the rear site and move it to the left.
To help you with adjustments, they sell rifle targets with grids at most sporting good stores as shown below.
After making all adjustments, double check, and check again! By zeroing your rifle at 50 yards, it allows you to put your point of aim on a target anywhere from 25-300 yards and still hit it since there is only around a 6″ difference from point of aim to point of impact (as seen on diagram above). Keep in mind conditions that can affect your zeroing including: temperature, altitude, and human error like flinching or poor rest. Now that you have learned how to zero an AR15 rifle, find what works best for you and your preferences.