The number one topic in every class and event is sighting-in and determining the “best” method for your AR-15. At Trace Armory Group, I’ve developed a proven sight-in process that I use with all students. This article will explain why I recommend my approach and provide insights to help you develop a process that works for you. While I aim to simplify complex concepts, this is an in-depth guide for serious shooters. Buckle up and dive in!

Carbine Guidelines of Use
Carbines are designed for accurate, multiple-shot engagements at unknown distances, typically within 300 yards, while ensuring effective terminal performance. Understanding these guidelines allows you to optimize sight settings and significantly enhance your shooting performance.

Definitions
Before diving into the details, let’s clarify some essential terms:

  • Sight-In: Adjusting the sighting system so that the bullet’s point of impact matches the point of aim at a specific distance.
  • Accuracy: The ability to consistently hit the intended target point (e.g., the bullseye).
  • Precision: The consistency of shot placement, regardless of whether it’s on the intended target.
  • Mechanical Offset: The distance between the sights and the bore line.
  • Sight Alignment: This means centering the front sight post in the rear aperture for fixed sights. For optics, it’s ensuring the reticle is centered without parallax.
  • Sight Picture: The target image is viewed through the sighting system.
  • Line of Sight: The visual plane connecting your eye, aiming device, and target.
  • Cone of Fire: The clustering of shots, influenced by carbine and ammunition        precision, measured in MOA or MIL.
  • Hold Off: Physically adjusting the point of aim to compensate for bullet trajectory or environmental factors.
  • Departure Angle: The upward angle of the bore to counteract gravity and extend bullet range.
  • MIL (Milliradian): An angular measurement used for precise adjustments, with 1 MIL equating to 3.6 inches at 100 yards.
  • MOA (Minute of Angle): An angular unit where 1 MOA equals approximately 1 inch at 100 yards.
  • IPHY (Inches Per Hundred Yards): A simplified version of MOA, assuming 1 inch per 100 yards.

Cone of Fire

The Cone of Fire integrates variables like muzzle velocity, bullet ballistic coefficient, and the carbine’s precision into a measurable pattern. A tighter Cone of Fire reflects greater consistency, demonstrating the combined performance of the carbine and ammunition. For example, a precision rifle with match-grade ammo    produces a smaller Cone of Fire than a standard carbine with bulk ammo.

Line of Sight, Bullet Trajectory, and Point of Aim
To ensure alignment between the line of sight, bullet trajectory, and point of aim, you must adjust the carbine’s departure angle. This involves fine-tuning your sighting device to match the bore’s angle to the line of sight.

A bullet fired from a horizontal barrel immediately begins to fall due to gravity as shown by the red line above.

Elevating the muzzle compensates for this Gravitational pull, allowing the bullet to reach    further distances while maintaining accuracy.

The Importance of a Repeatable, Adjustable Aiming Device
Aiming devices with repeatable and adjustable units (MOA, MIL, or IPHY) are essential for  precision. For instance, at 200 yards, a 1/2 MOA per-click optic moves the point of impact by 1.047 inches. This precision makes it easier to track bullet placement and adjust accordingly. For example, if your group is 4 inches low and 5 inches left at 200 yards, you would adjust your optic 3–4 clicks up and 4–5 clicks right to center the group.

Short-Range Sight-In

The misconception that short-range sight-ins are inherently accurate is a common pitfall. For example, with a 25-yard sight-in, each click of a 1/2 MOA optic adjusts the point of impact by only 0.130875 inches. This creates a false sense of     precision, as grouping inconsistencies can arise from varying points of aim.

Moreover, the belief that a 25-yard sight-in ensures accurate hits at 300 yards is a myth. While some rounds may strike the target, the overall grouping lacks precision. For optimal accuracy, a minimum sight-in distance of 100 yards is recommended.

However, I prefer a 200-yard sight-in for all barrel lengths in .223/5.56mm carbines, as it aligns the line-of-sight more effectively with the bullet trajectory and the cone of fire.

Summit Sight-In
A bullet’s trajectory resembles a parabolic arc, like a football pass. A summit sight-in is typically performed at 100 yards, minimizing hold-over adjustments for practical distances (e.g., muzzle to 150 yards). In most scenarios, aiming at the target’s center results in  consistent hits due to the carbine’s precision and manageable Cone of Fire.

 

 

 

Distance Sight-In
For sight-ins beyond the trajectory summit, the bullet crosses the line of sight twice: once at a closer range and again at the designated sight-in distance. This dual crossing offers flexibility. Common sight-in distances include 200, 250, or 300 yards, depending on the intended use.

As shown in the graphic above, a longer sight-in distance results in a shorter “near crossing” because the steeper angle of the bore line is needed to elevate the trajectory arc to the appropriate height.

  • Advantages: A properly chosen distance sight-in keeps the trajectory within target dimensions (e.g., a 40×20-inch human silhouette or a 14-inch square for competitions), reducing the need for hold-off adjustments.
  • Disadvantages: Longer sight-ins can cause the trajectory to rise too high above the line of sight. For example, a 400-yard sight-in results in a summit 11–12 inches above the line of sight, reducing hit probability at intermediate ranges.

Keep in mind that the table and chart above illustrate the ballistic trajectory’s center line. The actual shot grouping will form a dispersion pattern around this line, staying within a 5 MOA spread. For example, with a 200-yard zero, the projectile impacts 3.5 inches below the line of sight at 250 yards.

The image below highlights three key elements of a 250-yard target:

  • The red circle represents a 4 MOA reticle aimed high center of mass as seen through an AimPoint M68 at 250-yards.
  • The yellow circle illustrates a 5 MOA Cone of Fire at 250-yards.
  • The white circle marks the 3.5-inch drop from a 200-yard sight-in.

 

On January 28, 2025, I conducted a test at the Eastwood Outfitters Training Facility with the following rifle specifications:

  • Barrel: 10.5″ Nitride-Treated Chrome Moly Vanadium
  • Twist Rate: 1:7″
  • Chamber: 5.56 NATO
  • Gas System: Carbine-length
  • Sights: F-Marked Front Sight Post, A2 Flash Hider
  • Upper Receiver: Forged
  • Optic: AimPoint M68 (4 MOA RDS)
  • Ammunition: Defender Ammunition 55gr FMJ BT (Remanufactured)

The results confirm that a 5 MOA Cone of Fire remains the best universal standard for         carbines in rapid-fire scenarios under real-world conditions.

Watch the below YouTube video to see me shoot this test in real time.

As we’ve explored, shot placement is influenced by multiple factors, including the precision of your carbine, ammunition quality, and sight-in distance. A solid understanding of ballistic   concepts like the Cone of Fire and trajectory arc is crucial for maintaining accuracy, particularly at unknown distances where terminal performance matters most.

This article and more can be found in our North Carolina AR-15 Owners Manual you can download it for free!

John Boyette

By John Boyette

Hello! I am the Owner and Lead Trainer at Trace Armory Group. With over twenty years of dedicated experience in self-defense training, particularly specializing in home defense tactics, North Carolina Based. https://tracearmorygroup.com/pages/about-us

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