Understanding the Fundamentals of AR-15 Zeroing
Zeroing your AR-15 is one of the most critical skills in responsible rifle ownership and accuracy. Whether you’re a competition shooter, hunter, or home defense enthusiast, a properly zeroed rifle ensures your bullets hit where you aim. Unfortunately, many shooters either skip this process entirely or perform it incorrectly, leading to dangerous misses and wasted ammunition at the range.
The concept of zeroing involves aligning your rifle’s point of impact (where the bullet actually hits) with your point of aim (where your optics are aimed). This process compensates for the mechanical offset between your barrel and optics, ensuring predictable accuracy downrange.
What is a Battle Zero (BZO)?
A Battle Zero, or BZO, is a zeroing distance optimized for combat or defensive applications rather than precision shooting. Most military and tactical applications use a BZO of either 25 or 50 yards because it provides a practical compromise between close-range and mid-range accuracy. The advantage of a BZO is that it typically provides adequate accuracy across a wider range of distances without requiring holdover adjustments in realistic engagement scenarios.
For standard 5.56 NATO or .223 Remington loads with a 20″ barrel, a 25-yard zero will produce a point of impact approximately 2.5 inches high at 50 yards and level again around 200 yards. This means if you’re zeroed at 25 yards, you can aim center mass from contact distance out to 200 yards with minimal holdover adjustment.
The 25-Yard Zero Method
The 25-yard zero is the fastest and most practical method for setting up a duty or home defense AR-15. Here’s the step-by-step process:
- Set up your target: Place a paper target with a clear aiming point 25 yards downrange. Most shooters use a bullseye target or a small square outline.
- Establish a stable shooting position: Use a benchrest, sandbags, or other support to eliminate as much shooter error as possible. The goal is to isolate the rifle’s accuracy from your own fundamental inconsistencies.
- Fire a group: Send 3-5 rounds downrange, aiming at the same point on the target while maintaining consistent sight picture and trigger control.
- Measure your group: Check where your shots landed relative to your aim point. You’re looking to establish your natural point of aim.
- Adjust your sights: If using iron sights, adjust the rear sight using the elevation and windage screws. Most AR-15 rear sights adjust in 1/2-minute-of-angle (MOA) increments. If using an optic, most have turrets that adjust in 1/4 MOA or 1/2 MOA clicks. Remember: “up” on the turret moves the impact up, right moves it right. Rotate the turret in the appropriate direction until your group is centered on the target.
- Fire another group and verify: After making adjustments, fire another 3-5 round group to confirm your zero.
The 50-Yard Zero Method
A 50-yard zero provides better accuracy at extended distances compared to a 25-yard zero and is often preferred by competition shooters and hunters. The 50-yard process is identical to the 25-yard method, but you’ll extend the distance to 50 yards. The advantage is that it positions your weapon for more consistent accuracy from 50 yards out to about 250 yards.
The main difference shooters notice is that the 50-yard zero typically puts your point of impact slightly lower at contact distance than the 25-yard zero, requiring small holdover adjustments for extremely close shots. However, in practical defensive or hunting scenarios, this is negligible.
The 100-Yard Zero Method
The 100-yard zero is the traditional benchmark for precision rifle shooting and is preferred by long-range shooters and hunters pursuing larger game. This distance is far enough away that shooter error becomes more apparent, so proper technique is essential.
At 100 yards, your adjustment increments become more critical. Most optics using 1/4 MOA per click will require fine precision. The 100-yard zero provides the flattest trajectory from 75 to 200 yards, making it ideal if you plan to engage targets beyond typical defensive distances.
Understanding Bullet Drop and Holdovers
Once your rifle is zeroed, you need to understand how bullet drop affects your accuracy at various distances. A common misconception is that once zeroed, your rifle is accurate “everywhere.” In reality, your bullets follow a ballistic arc and drop increasingly as distance increases.
For a 5.56 NATO round fired from an AR-15 zeroed at 100 yards, you can expect approximately 8-10 inches of drop at 300 yards, depending on powder charge, bullet weight, and ambient conditions. This is why understanding your weapon’s ballistics and employing holdover techniques or adjustable optics is critical for precision work beyond your zero distance.
Common Zeroing Mistakes to Avoid
Zeroing in high wind: Wind conditions significantly affect bullet trajectory. Always zero in calm conditions or ensure you understand how wind is affecting your shots.
Using inconsistent shooting technique: Poor trigger control, unstable position, or movement during the shot will produce inaccurate groups. Use a sandbag rest or benchrest during zeroing.
Adjusting too aggressively: Make small adjustments and verify with additional shots rather than making large changes between groups.
Zeroing with damaged ammunition: Inconsistent ammunition produces inconsistent results. Use quality, consistent ammunition for zeroing.
Forgetting to verify after mounting optics: If you change optics or mounts, always verify your zero. Even minor mount changes can shift impact.
Practical Zero for Home Defense
For home defense applications, a 25-yard zero offers the best all-around solution. The distances inside most homes rarely exceed 25 yards, and this zero provides adequate accuracy for the threat distances you’re most likely to encounter. The advantage of the shorter zero distance is faster setup time and the ability to verify your zero regularly at indoor ranges.
Regardless of your chosen zero distance, verify your rifle’s accuracy regularly and understand your weapon’s ballistics for your intended use. A properly zeroed AR-15 is a reliable tool that you can depend on when accuracy matters most.
