Bore sighting is a method of roughly aligning a firearm’s barrel with its sights before ever firing a shot. The goal is simple: get your first rounds close enough to the target that you can see where they hit and make fine adjustments from there. Without bore sighting, a newly mounted scope could be so far off that your shots miss the paper entirely at the range, leaving you with no reference point to work from.
How Bore Sighting Works
Every firearm has two imaginary lines that matter. The first runs straight through the center of the barrel, called the bore axis. The second runs through the center of your scope or iron sights. Bore sighting aligns these two lines so they converge on roughly the same point downrange. Once they’re close, your first live shots will land on or near the paper target, and you can dial your scope in from there.
The simplest version requires no tools at all. With bolt-action rifles, you remove the bolt, look straight through the barrel from the back, and center the bore on a target. Then, without moving the rifle, you adjust your scope’s crosshairs to sit on that same target. Many experienced shooters prefer this free method over any commercial tool, finding it just as reliable for getting on paper.
Types of Bore Sighting Tools
Two main categories of tools exist: laser bore sighters and optical collimators. Each takes a different approach to the same problem.
Laser bore sighters are the most popular consumer option. These are small devices shaped like a cartridge that you insert into the chamber of your firearm. They project a laser dot onto a target, and you adjust your scope until the crosshairs sit on that dot. They’re caliber-specific, though many systems use a base laser (often sized for .223 or .30 Carbine) with interchangeable arbors that adapt it to fit calibers ranging from .40 S&W up to .50 BMG. Universal bore sighters that attach to the muzzle also exist, but they carry a serious safety risk: if you forget to remove one before firing, it can destroy your barrel.
Optical collimators are older-style tools that attach to the muzzle and use a grid pattern visible through your scope. You align the scope’s crosshairs with the grid to establish a reference point. Collimators have a loyal following among hunters who use them not just for initial setup but as a quick check before a hunt. If your rifle took a bump during travel or you’ve remounted a scope, a collimator gives you a repeatable visual reference to confirm nothing has shifted. Some shooters find collimators more consistent than laser bore sighters, though most commercial collimators appear to come from the same factory regardless of brand, with prices starting around £40 (roughly $50).
Bore Sighting Is Not Zeroing
This is the single most important thing to understand: bore sighting gets you close, but it does not zero your firearm. The two are different steps in the same process.
Bore sighting aligns the barrel and sight using a visual or laser reference. It ignores everything that happens after the bullet leaves the barrel. Zeroing goes further by adjusting your sight so the point of aim matches the actual point of impact, accounting for gravity, wind, barrel harmonics, and the physical distance between your scope and the bore. A bore-sighted rifle will typically put shots within a few inches of your aim point at 25 to 50 yards, which is close enough to see where you’re hitting and start making real adjustments.
A common mistake is assuming that because a rifle is bore-sighted, it’s ready to shoot accurately. Some shooters hit near the bullseye at 25 yards and assume they’re set, only to find they’re several inches off at 100 yards. This happens because gravity pulls the bullet downward over distance, and the slight offset between the scope (which sits above the barrel) and the bore itself creates a geometry that only lines up perfectly at one specific range. That range is chosen during zeroing, not bore sighting.
What to Expect at the Range
A well-executed bore sight, whether done by eye or with a tool, will reliably get your first shots on paper at 25 to 50 yards. At those distances, you can expect your point of impact to land within a few inches of your crosshairs. One shooter described bore sighting at 20 yards indoors, then finding shots landed within 6 inches at 50 yards, and within an inch at 100 yards after a few adjustments.
At 100 yards, bore-sighted shots typically need fine-tuning. The shift between where the laser or bore alignment predicted and where the bullet actually lands becomes more pronounced as distance increases. Several adjustment shots are usually required to walk the scope into a true zero. This is normal and expected. The bore sight saved you the frustration of shooting blind; the live-fire zeroing process finishes the job.
Beyond Rifles
Bore sighting isn’t limited to hunting rifles and range guns. The same principle applies to any weapon system that needs its sights aligned with its barrel. During World War II, dedicated boresighting ranges were built at military airfields to align the fixed guns on fighter aircraft. The process was more complex than a single rifle: planes with multiple guns had to align all their bore axes to converge on a single sight axis at a specific distance. Aircraft were anchored to the ground by their wings and tail during test-firing to hold them in place.
Modern military applications extend to tank main guns, vehicle-mounted weapons, and other crew-served systems. The physics are identical to what happens with a deer rifle. You align the barrel with the sight, then refine through actual firing.
Practical Tips for Bore Sighting
If you’re bore sighting for the first time, the process is straightforward. Secure your rifle in a stable rest, whether that’s a proper gun vise, sandbags, or a bipod on a flat surface. Stability matters because any movement between aligning the bore and adjusting the scope defeats the purpose.
For the bolt-removal method, pick a small, distinct aiming point at 25 to 50 yards. A doorknob, a specific mark on a target, or any high-contrast object works. Center it in the bore, then adjust the scope without touching the rifle. For laser bore sighters, insert the cartridge-style device into the chamber, project the dot onto a target, and adjust your scope to match. Always remove the laser device before loading any ammunition.
Try to bore sight at roughly the same distance you plan to zero. If you’re heading to a 100-yard range, bore sighting at 50 yards gets you closer than bore sighting at 10 yards, because gravity’s effect on the bullet at those two distances is very different. And regardless of the method you choose, plan to bring enough ammunition to the range for proper zeroing. Bore sighting saves you rounds by getting you on paper faster, but expect to fire 10 to 20 rounds to walk your scope into a precise zero at your chosen distance.