Mounting
How to Bore Sight a Scope
Quick answer
Bore sighting gets a newly mounted scope close enough to land on paper, not zeroed; on a bolt action, remove the bolt, look through the bore at a distant object, and adjust the reticle to match without moving the rifle, which is more honest than a cheap laser kit whose caliber adapter can point somewhere the barrel does not.
Bore sighting solves exactly one problem: after mounting a scope, nobody knows where the rifle is actually pointed relative to where the reticle is aimed, and without some form of bore sighting the first live shots can miss the paper entirely. What it does not do is replace a real zero. It gets you close enough that your first few live rounds are corrections rather than a blind search for where the target went.
The most reliable method on a bolt action costs nothing but a distant object to look at. Remove the bolt, look straight through the empty bore at something far away, and adjust the reticle to match that same point without moving the rifle. Every step of that process is visible and self-checking. A laser bore sighter that inserts into the muzzle or chamber via a caliber-specific adapter is faster, but it introduces one more part that has to be perfectly square, and a loose or mismatched adapter can point the laser somewhere the barrel genuinely does not.
How to bore sight a scope
- Clear the rifle. Open the action and confirm the chamber is empty and the magazine is out. This step is not optional even though no round will be fired: bore sighting always happens with an open, empty action.
- Secure the rifle on a stable rest, aimed at a distant, distinct object. Set the rifle on sandbags or a front rest pointed at something far away with sharp detail, such as a chimney corner, a utility pole marking or a distant sign, ideally 100 yards or more away. The distance and detail matter because a nearer or vaguer target makes small alignment errors harder to see.
- For a bolt action, remove the bolt. With the action open and the bolt removed, look through the empty receiver and down the bore itself. Center the distant object in the bore as precisely as you can, using small shifts of the sandbags rather than touching the rifle directly, which can move your aim point.
- Without moving the rifle, look through the scope. Keeping the rifle exactly as positioned, move only your eye to the scope's eyepiece. The distant object you centered in the bore will likely not be centered in the reticle yet, and that gap is what bore sighting corrects.
- Adjust the turrets, not the rifle, until the reticle matches the bore. Dial the elevation and windage turrets until the reticle's center sits on the same distant object the bore is centered on. Check back through the bore periodically to confirm the rifle itself has not shifted on the rest while you worked the turrets.
- For an action where the bolt cannot be removed, use a bore sighter instead. On a lever action, an AR-pattern rifle or anything else where looking through the bore is not practical, use a magnetic or laser bore sighter such as the Wheeler Professional Laser Bore Sighter with Magnetic Connection at $97.68, or the laser sighter included in a kit such as the Wheeler Engineering Ultra Scope Mounting Kit with Laser Bore Sighter and Reticle Leveling System, following its specific setup instructions.
- Replace the bolt carefully without disturbing the rifle position. Reinsert the bolt gently. If the rifle shifts on the rest while doing this, recheck alignment through the bore before trusting the bore sight result.
- Move to a live fire zero on a safe, legal backstop. Bore sighting is finished once the reticle and bore agree on the same distant point. Treat this only as having gotten the rifle onto the paper, and proceed to a full zero with live rounds fired in groups, on a supervised range or a safe, legal backstop.
Comparing the honest methods against the shortcuts
Every bore sighting method trades some combination of speed, cost and honesty about its own accuracy. None of them is a zero, but some are far more trustworthy about how close they actually got you.
The bolt-out look-through method is self-checking and free, while a laser kit with a caliber adapter is faster but only as accurate as the fit of that adapter in the bore.
Shooter convention
| Method | Works on | Honest limitation |
|---|---|---|
| Bolt-out look-through | Bolt actions where the bolt is removable | Slower, and requires a genuinely distant, distinct object to aim at |
| Magnetic bore light | Any action, aids the look-through method | Illuminates the bore but does not replace centering the reticle yourself |
| Laser bore sighter, caliber adapter | Actions where the bolt cannot be removed | Accurate only if the adapter fits the specific bore diameter squarely; a loose or mismatched adapter can point the laser off axis |
| Collimator or arbor-mounted sighter | Muzzle-inserted on many actions | Depends on a snug, square fit in the muzzle, similar caveat to caliber adapters |
A budget laser kit with a universal caliber adapter is the method most likely to disagree with reality without telling you it has, because nothing about a slightly loose fit looks wrong from the outside.
Why a cheap laser kit can be worse than no bore sighter at all
A laser bore sighter that inserts via a caliber-specific adapter is only as accurate as the fit of that adapter inside the bore. The adapter has to sit perfectly centered and square to the bore axis for the laser to project along the same line the bullet will actually travel. A universal adapter kit covering many calibers achieves that fit by compromise, and a loose or slightly tilted adapter points the laser at a spot the barrel is not actually aimed at, with nothing about the setup indicating anything is wrong.
The bolt-out look-through method has no equivalent failure point, because you are looking directly down the actual bore rather than trusting an intermediate part to represent it. It costs more time and it does not work on every action type, which is the real reason laser kits exist, but on a bolt action there is no more honest method available before live fire.
Sources
- Owner-review consensus on bore sighting methods and their limitations
- Manufacturer instructions for laser and magnetic bore sighting tools
Frequently asked questions
Does bore sighting replace zeroing a rifle?
No. Bore sighting only gets the reticle and the bore agreeing on the same distant point, which is enough to land shots on paper. It does not account for how the bullet actually flies, ammunition-specific ballistics, or small errors in the process itself. A live-fire zero with real groups measured and corrected is still required afterward.
Can I bore sight without removing the bolt?
Yes, using a magnetic or laser bore sighter designed for actions where the bolt is not removable, such as most semi-automatic and lever action rifles. These tools are convenient but their accuracy depends entirely on how squarely they fit the bore, so treat the result as an estimate to be confirmed with live fire just as you would the bolt-out method.
Are cheap laser bore sighter kits accurate?
Only as accurate as the caliber adapter's fit in the bore. A universal kit covering many calibers uses adapters sized by compromise, and a loose or slightly tilted adapter points the laser somewhere the barrel is not actually aimed, with no visible sign anything is wrong. They can still get a rifle onto the paper, but treat the result skeptically.
What should I aim at when bore sighting?
Something distant and visually distinct, ideally 100 yards or more away, such as a chimney corner or a clearly marked utility pole. A closer or vaguer target makes small centering errors harder to see through both the bore and the scope, which reduces how useful the whole exercise is.
Why do I still need to fire live rounds after bore sighting?
Because bore sighting only aligns the reticle with the bore's physical axis at the moment you set it up. It cannot account for how the bullet's actual trajectory behaves at distance, small mounting or leveling errors, or the specific ammunition you use. Live fire with measured groups is the only step that confirms where the rifle is actually shooting.
Is bore sighting necessary if I am zeroing at 25 yards anyway?
It is still worth doing. Bore sighting first means your very first live rounds at 25 yards are more likely to land on the paper at all, saving ammunition and time compared to searching for the group cold. It is a complement to a 25 yard zero, not a substitute for one, since neither step alone replaces the other.
Researched, not professional advice. This page is compiled from published manufacturer specifications, published optical and ballistic formulas, and owner-review consensus, not hands-on testing. Figures described as a rule of thumb are shooter convention rather than sourced numbers, and they are labelled that way wherever they appear. Ballistic figures come from a point mass model using the ballistic coefficient the maker publishes, so treat them as a starting point and confirm them on paper at a measured distance. Confirm your firearm is unloaded with the action open before you mount, level, torque or bore sight anything. Verify a zero only on a supervised range or a safe, legal backstop, know what lies beyond your target, and follow the law where you hunt and shoot, including rules on land access and permitted cartridges.