How to Zero in a Red Dot Sight

How to Zero in a Red Dot Optic Sight for an AR-15 Rifle

Zeroing in a red dot optic sight for your AR-15 rifle is a critical step to ensure accuracy and precision when shooting. Red dot sights are popular among shooters for their speed and ease of use, but they still require proper zeroing to hit your target consistently. In this article, we will guide you through the step-by-step process of zeroing in your red dot sight.

What is Zeroing?

Zeroing, also known as sighting in, is the process of adjusting your red dot optic sight so that the point of impact (POI) aligns with the point of aim (POA) at a specific distance. In simpler terms, it’s the process of making sure that when you aim at a target, the bullets or rounds hit exactly where you intend them to.

Rifle Ammo in Stock

Tools and Equipment Needed:
Before you begin the zeroing process, ensure you have the following tools and equipment:

AR-15 Rifle: Make sure your rifle is in good working condition and properly cleaned.

Red Dot Optic Sight: Ensure it is securely mounted on your rifle and properly aligned with the bore.

Ammunition: Use the same type and brand of ammunition you plan to use regularly for shooting.

Shooting Rest or Sandbags: These provide stability and support during the zeroing process.

Target: A paper target with a clear aiming point is essential. You can purchase specialized zeroing targets or create your own.

Allen Wrench or Screwdriver: To make adjustments on your red dot sight.

Eye and Ear Protection: Safety should always be a priority.

Step-by-Step Guide to Zeroing Your Red Dot Optic Sight:

Follow these steps to zero in your red dot sight:

  1. Choose a Zeroing Distance:
    Decide on the distance at which you want to zero your red dot sight. A common choice is 25 yards for rifles like the AR-15, as it is a good compromise between close-quarters and mid-range shooting. However, you can choose a different distance depending on your needs.

  2. Set Up Your Shooting Rest:
    Find a stable shooting platform. You can use a shooting rest or sandbags to support your rifle. Ensure the rifle is secure and immobile.

  3. Prepare Your Target:
    Place your target at the chosen zeroing distance (e.g., 25 yards) and make sure it is securely attached to a backstop. Ensure the target is at eye level and well-lit.

  4. Boresight Your Rifle:
    Before making any adjustments to your red dot sight, it’s a good practice to boresight your rifle. To do this:

a. Remove the bolt or BCG (bolt carrier group) from your rifle.

b. Look through the bore and align it with the target. Center the target in the bore.

c. Without moving the rifle, adjust your red dot sight’s windage and elevation settings so that the dot is also centered on the target.

  1. Initial Shots:
    Load a few rounds of ammunition and take a few shots at the target. This will help you get on paper and see where your rounds are hitting in relation to your point of aim.

  2. Make Adjustments:
    Based on where your initial shots landed, use the adjustment knobs on your red dot sight to move the point of impact (POI) towards the point of aim (POA). Here’s how to do it:

a. Windage Adjustment: If your shots are hitting left or right of the target, use the windage knob to move the POI horizontally.

b. Elevation Adjustment: If your shots are hitting high or low, use the elevation knob to move the POI vertically.

c. Follow the manufacturer’s instructions for your specific red dot sight to know which direction to turn the adjustment knobs. Typically, clockwise adjustments move the POI up and right, while counterclockwise adjustments move it down and left.

  1. Repeated Shots and Fine-Tuning:
    Fire a series of shots, making small adjustments each time, until your shots consistently hit the center of your target. It may take some trial and error to achieve this.

  2. Confirm Zero:
    Once your shots are consistently hitting the center of the target at the chosen zeroing distance, fire a few more rounds to confirm that your zero is consistent.

  3. Record Your Zero:
    Make note of the adjustments you made on your red dot sight so that you can easily return to your zero if needed in the future.

  4. Test at Different Distances:
    After zeroing at your chosen distance, it’s a good practice to test your rifle at other distances to understand how the bullet’s trajectory changes. This will help you make informed adjustments in the field.

Final Thoughts:

Zeroing in a red dot optic sight for your AR-15 rifle is a critical step in achieving accuracy and consistency in your shooting. Remember that environmental factors such as wind and ammunition choice can also affect your point of impact, so practice and testing under various conditions are essential. Always follow safety protocols when handling firearms, and consider seeking the guidance of a qualified instructor if you are new to shooting or zeroing optics. With patience and practice, you can achieve a precise and reliable zero for your red dot sight, improving your shooting performance.

Zero in with Aimpoint shooting target
aimpoint target1. Set up the Aimpoint target at 25 meters.

2.Place firearm in solid rest and center dot on target.

3.Take one shot and inspect the point of impact.

See image “Target 1” above

This target shows that the point of impact was too much to the right and a little too low

Check out the Aimpoint PRO Patrol Rifle Optic @

aimpoint target 24. With the information given on top of the printed Aimpoint shooting target, and by counting the number of squares between the actual point of impact and the desired point of impact on the target, you can quickly and precisely determine how many clicks you need to move the adjustment screws in order to zero your sight.

See image “Target 2”, in the column to the right here

NOTE: The number of clicks per square is determined by the distance to your target.



  • Take another shot to check that the point of impact is centered. If you still need to adjust slightly, repeat the procedure.
  • Check out the Aimpoint 2OA CompM3 Sight @

    Question: What is a good entry level red dot scope if am just starting out?

    First things first, let’s establish what the Bushnell TRS-25 is NOT – it is NOT an Eotech or Aimpoint red dot sight.

    It is also less than 20% of the cost of either of those sights.

    That being said, for the price, the Bushnell Trophy Red Dot TRS-25 3 MOA Red Dot Reticle Riflescope is an excellent sight. The construction is solid, it attached to the flat top rail of my AR15 easily and securely. The rubber lens covers, attached to each other by a small rubber cord, are sufficient for protecting the lenses from most objects and debris while remaining in place.

    Question: My red dot battery keeps going dead after only a few weeks. What am I doing wrong?  You are probably leaving it on the 1 through 11 setting (increase of red dot). It needs to be set on 0 (zero) after you finish for day.  If you leave it on 1 – it will slowly drain the battery.

    Question: How to adjust Bushnell trs-25? Check out the info and review in the video below.

    Question: How can I find out more about the NRA? Check out the website here:

    Best AR-15 under $700

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