Bore sighting is a method of pre-aligning a firearm’s sights or scope with the direction the barrel is actually pointing. The goal is simple: get your optic close enough to where the bullet will land that your first few shots at the range hit the paper target instead of sailing off into the dirt. It’s a rough alignment, not a finished zero, and it can save you significant time and ammunition when setting up a new scope or rifle.
How Bore Sighting Works
Every firearm has two lines that matter for accuracy. The first is the bore axis, which is the straight line running through the center of the barrel. The second is the line of sight through your scope or iron sights, which sits above the barrel. These two lines aren’t parallel by default, especially when you mount a new optic. Bore sighting brings them into rough agreement so they both point at the same spot on a target at a given distance.
Think of it this way: if your scope is looking three feet to the left of where the barrel is pointing, your first shots will miss the target entirely. You won’t even know which direction to adjust. Bore sighting closes that gap so your initial shots land on or near the target, giving you a starting point for fine-tuning.
Manual Bore Sighting on a Bolt Action
The simplest method requires no tools at all, just a bolt-action rifle and a stable rest. You remove the bolt, set the rifle on sandbags or a shooting rest so it doesn’t move, and look straight through the breech end of the barrel. You’ll see a small, bright circle of light at the muzzle end, and through it, your target. Position the rifle so that circle is centered on your target at roughly 25 to 100 yards.
Without moving the rifle, look through the scope. The crosshairs will almost certainly be pointing somewhere else. Use the scope’s adjustment turrets to move the crosshairs onto the same spot you see through the bore. Go back and forth between the bore view and the scope view, making small adjustments, until both are aimed at the same point. Then replace the bolt. The whole process takes a few minutes.
This method only works on firearms where you can physically look through the barrel from the rear, which limits it to bolt-action rifles and single-shot firearms with removable actions.
Laser Bore Sighters
For semi-automatic rifles, lever actions, and other firearms where you can’t see through the barrel, laser bore sighters solve the problem. These devices project a laser dot onto a target, showing exactly where the barrel is pointing. You then adjust your scope’s crosshairs to match the laser dot.
There are three main types:
- In-chamber bore sighters are shaped like a cartridge and drop into the chamber just like a round of ammunition. They project a laser beam down the bore and out the muzzle. These are caliber-specific, so you need one matched to your firearm’s chambering. Because the laser travels the full length of the bore, they tend to be very accurate for initial alignment.
- Arbor-based bore sighters use interchangeable adapters that fit inside the muzzle end of the barrel. One unit can work across multiple calibers by swapping arbors, though getting the fit right sometimes requires a little fiddling. These are popular for shooters who own rifles in several different calibers.
- Magnetic muzzle-mounted bore sighters attach to the outside of the muzzle with a strong magnet. They’re the easiest to use and work across many barrel diameters without caliber-specific parts, though they align to the outside of the barrel rather than the bore itself.
Laser visibility depends on lighting conditions. In testing, some units are only visible to about 50 yards on a white target in daylight. Early morning or indoor ranges with controlled lighting give you the best results.
Why 25 Yards Is the Standard Starting Distance
Most bore sighting is done at 25 yards, especially at indoor ranges where that’s the maximum available distance. But there’s a practical reason beyond convenience. Because a rifle scope sits above the barrel (typically 1.75 to 2.5 inches higher), the bullet’s path and the scope’s line of sight cross at specific distances. At 25 yards, a bullet from most deer-caliber rifles will impact about 1 inch below the point of aim if the scope is properly bore sighted. That 1-inch-low impact at 25 yards translates to being on target at 100 yards for most centerfire rifle cartridges.
For AR-style rifles, where the scope sits higher above the bore (around 2.5 inches), aim for about 1.5 inches low at 25 yards to land on target at 100. Keep in mind that scope adjustments have a magnified effect at short range: it takes four times as much turret adjustment to move the bullet’s impact at 25 yards compared to 100 yards, so make small changes.
Bore Sighting Is Not Zeroing
This is the most important distinction to understand. Bore sighting gets you on paper. Zeroing gets you on target. They are not the same thing.
Bore sighting only aligns two straight lines: the bore axis and the scope’s line of sight. It cannot account for gravity pulling the bullet downward in flight, wind pushing it sideways, or the unique vibration patterns of your specific rifle and ammunition combination. A bullet that leaves the barrel pointed at a target 100 yards away will always drop below that point by the time it arrives. Only live-fire zeroing, where you shoot actual rounds and adjust based on where they hit, can account for these real-world factors.
Some shooters bore sight at 25 yards and assume they’re zeroed because the first few shots are close to the bullseye. But a rifle zeroed at 25 yards can easily be several inches off at 100 yards. Bore sighting is the starting point. Live fire is the finish.
What You Need to Bore Sight
At minimum, you need a stable rest that holds the rifle completely still. Sandbags work well, and purpose-built gun vises or cleaning rests are even better. Any movement between checking the bore and checking the scope will throw off your alignment. You also need a visible target at a known distance, and for laser methods, a bore sighter matched to your firearm.
For the manual method on a bolt-action rifle, you need nothing beyond the rest and a target. For semi-autos and lever actions, a laser bore sighter is essentially required unless you want to skip straight to live-fire zeroing at close range, burning through extra ammunition to walk your shots onto paper. A good laser bore sighter can get you within about 2 MOA (roughly 2 inches at 100 yards) of your intended point of impact, meaning your very first live round should be close enough to see on the target and begin fine adjustments.