There’s a special kind of satisfaction that comes from hitting exactly where you aim, especially with a rifle as versatile as the AR-15. Whether you’re a new owner fresh from the gun store or a seasoned shooter setting up a new optic, the process of aligning your sights with your point of impact is a fundamental skill. It’s the bridge between simply pulling the trigger and making an accurate shot with confidence. Getting it right is simpler than you might think, and it all starts with a solid foundation.
This guide is designed to walk you through the entire process, step-by-step. We’ll cover everything from the essential gear you’ll need to the final adjustments that will make your rifle a true extension of your intent. By the end of this complete walkthrough on how to sight in an AR 15, you’ll have the knowledge and the confidence to get your rifle hitting center mass, ensuring it’s ready for the range, the field, or any situation where precision matters.
Gathering Your Gear and Preparing Your Rifle
Before you head to the range, a little preparation goes a long way. First, you’ll need a solid rest. A proper shooting bench with sandbags is ideal, as it supports the rifle steadily and removes most of the human error from the equation. If that’s not available, a bipod combined with a rear bag works very well. You’ll also need your targets; a simple bullseye target with a clearly defined aiming point is perfect for this task. Don’t forget a screwdriver or the specific tool for your sight’s adjustment dials, along with eye and ear protection, of course.
Start with a clean rifle. Ensure all the mounting screws for your optic or iron sights are properly tightened to the correct torque specifications. A loose sight will never hold zero. If you’re using a magnified optic, take a moment to set the diopter on the eyepiece so the reticle appears sharp and clear to your eye. This small step can make a big difference in your ability to aim precisely.
The Step-by-Step Process for How to Sight in an AR 15 [A Complete Walkthrough]
The most common and effective method for sighting in an AR-15 is to start at 25 yards to get on paper quickly, then confirm and fine-tune at 100 yards. This saves time, ammunition, and frustration.
Step 1: The 25-Yard Bore Sighting Method
If possible, begin with a rough bore sight. Remove the upper receiver from the lower and safely place it in a stable rest. Looking directly through the barrel (from the chamber end), center the target’s bullseye. Without moving the rifle, adjust your sights or optic until the reticle is also centered on that same bullseye. This isn’t for precision, but it will get your first shots somewhere on the paper target.
Step 2: Firing Your First Three-Shot Group
Set up your target at 25 yards. Using your steady rest, aim directly at the center of the bullseye and fire a group of three shots. Take your time, focusing on a smooth trigger press and consistent follow-through. The goal is a tight, grouped group of holes on the target.
Step 3: Making the Initial Adjustments
Now, find the center of your three-shot group. Let’s say your group is four inches low and two inches to the left of the bullseye. Here’s where you’ll use your sight’s adjustment dials. Most scopes and red dots adjust in Minutes of Angle (MOA), where one click typically moves the point of impact ¼ inch at 100 yards. Since you’re at 25 yards—one-quarter the distance—each click will now move the impact ¼ of that amount, or about 1/16 of an inch.
To correct our example: To move the impact up four inches, you would adjust the elevation knob in the “UP” direction. Since each click is 1/16″ at this range, you’d need 64 clicks (4 inches / 0.0625 inches per click). To move the impact right two inches, you’d adjust the windage knob in the “RIGHT” direction for 32 clicks. After making these adjustments, fire another three-shot group. It should now be very close to, or directly on, the bullseye.
Step 4: Confirming Your Zero at 100 Yards
Once you’re centered at 25 yards, move your target out to 100 yards. Fire another careful three-shot group. A proper 100-yard zero means your bullets should impact very close to your point of aim. Make any final, fine-tuning adjustments to the windage and elevation based on this 100-yard group. Remember, at this distance, each click on a standard ¼ MOA sight will move the point of impact by ¼ inch.
Helpful Tips for a Perfect Zero
Consistency is key. Always sight in from a solid, stable rest to isolate the rifle’s performance from your own shooting technique. Let your barrel cool between groups; a hot barrel can warp slightly and change your point of impact. Also, use the same ammunition you plan to use for shooting or hunting. Different brands and bullet weights can have significantly different points of impact.
If you’re using iron sights, the principle is the same: move the rear sight in the direction you want the bullet to go. If your shots are hitting to the left, move the rear sight aperture to the right. The same goes for front sight posts—to raise the point of impact, you would lower the front post.
Wrapping Up Your Sighting Session
Taking the time to properly sight in your AR-15 is one of the most rewarding tasks a shooter can do. It builds a fundamental connection between you and your firearm, fostering confidence and competence. The process of starting at 25 yards to get on paper and then confirming at 100 yards is a time-tested method that ensures efficiency and accuracy. With your rifle now zeroed, you can head to the range or the field knowing that when you aim, your bullet will follow.