Boresighting is a method of roughly aligning a firearm’s sights with where the barrel is actually pointing, so your first shots at the range land on or near the target. It’s a preliminary step done before zeroing, not a replacement for it. Think of it as getting your scope in the ballpark so you can fine-tune with live ammunition instead of wasting rounds trying to figure out where your shots are going.
Why Boresighting Matters
When you mount a new scope or swap optics on a rifle, the reticle (the crosshair you see through the scope) and the bore (the inside of the barrel) are almost never pointing at the same spot. Without boresighting, your first shot at 100 yards could miss the paper entirely, leaving you with no reference point for adjustments. You’d burn through ammunition just trying to get a shot on target.
Boresighting solves this by aligning the scope’s reticle with the barrel’s line of sight before you fire a single round. The goal is simple: get on paper. Once your shots are landing somewhere on the target, you can make precise adjustments during zeroing.
Three Common Methods
Visual Boresighting
This is the simplest approach and requires no extra tools, though it only works with firearms that let you see straight through the barrel from the back of the receiver. Bolt-action rifles are ideal because you just remove the bolt.
Start with an unloaded rifle secured in a vise or a stable rest. Movement is the enemy here, so the gun needs to stay perfectly still throughout. Place a target about 25 yards downrange. Look through the barrel from the back of the receiver and adjust the rifle’s position until the center of the target sits in the middle of the bore. Then, without moving the gun at all, look through your scope and use the windage and elevation turrets to move the reticle to the target’s center.
You’ll likely need to go back and forth a few times. Look through the bore, confirm the target is still centered, then look through the scope and adjust. Each pass gets you closer until both the bore and the reticle are pointed at the same spot. Tighten down your scope ring screws when you’re finished.
Laser Boresighters
A laser boresighter is a small device that fits into the chamber or muzzle of your firearm and projects a laser dot onto the target. You then adjust your scope’s turrets until the reticle lines up with the laser dot. This method works with nearly any firearm, including lever-actions, semi-automatics, and other designs where you can’t see through the barrel. Make sure you’re using the correct caliber adapter, and insert the device gently to avoid scratching the bore or damaging the chamber.
One critical safety point: always remove the boresighter before loading or firing. A device left in the barrel creates an obstruction that can cause serious damage to the firearm and injure anyone nearby.
Optical Collimators
A collimator inserts into the muzzle end of the barrel and uses a reflective surface and lenses to project a grid pattern that you can see through your scope. You adjust your turrets until the scope’s reticle aligns with the center of that grid. Collimators don’t require batteries and tend to be durable, making them a reliable option for repeated use.
Why 25 Yards Is the Starting Point
Most shooters boresight at 25 yards because the target is close enough to see through the barrel with the naked eye and large enough that even a rough alignment puts shots on paper. There’s also a practical math advantage: it takes four times the scope adjustment to move bullet impact at 25 yards compared to 100 yards, so small turret changes produce noticeable shifts on close targets.
A useful rule of thumb for deer rifles: boresight at 25 yards and aim for an impact about 1 inch low. That starting point typically puts you close enough to finalize your 100-yard zero in just a few shots.
Boresighting Is Not Zeroing
This is the most common misunderstanding. Boresighting aligns the scope with the bore, but it does not account for what happens to the bullet after it leaves the barrel. Gravity pulls the bullet downward over distance, and wind pushes it sideways. A rifle that hits the bullseye at 25 yards after boresighting can easily be several inches off at 100 yards because of these external factors.
Zeroing is the process of firing live rounds at your intended distance and making fine adjustments to the scope until the point of impact matches the point of aim. That’s where you account for bullet drop, your specific ammunition, and real-world conditions. Boresighting just gets you close enough that zeroing doesn’t take all day.
When to Boresight
Any time the relationship between your barrel and your optic changes, boresighting is worth repeating. The most obvious scenario is mounting a new scope, but it also applies after replacing scope rings, swapping between optics on a shared rifle, or if the gun has taken a hard impact (like a fall during a hunt). If your scope’s mounting hardware has loosened for any reason, re-boresighting gives you a quick baseline before you confirm with live fire.
Before you start, verify that your scope and rings are securely fastened. Loose hardware will shift during shooting, and no amount of boresighting will help if the scope moves between shots.
What to Expect at the Range
After boresighting, your first live shots at 100 yards should land somewhere on a standard paper target. From there, you fire a group of three to five rounds, note where they cluster, and adjust your turrets accordingly. Most shooters can achieve a solid zero in 10 to 20 rounds after a proper boresight, compared to potentially burning through a box or more without one.
With ammunition prices running anywhere from $0.50 to over $3.00 per round depending on caliber, those saved shots add up quickly. More importantly, you spend less time frustrated and more time refining your actual zero.