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“Sighting in a scope” means adjusting your rifle scope so the crosshairs line up with where the bullet actually hits at a set distance. This helps your point of aim match your point of impact.
At a Glance:
More than 52.7 million people take part in target and sport shooting across the United States, and most of them started right where you are now. Learning how to sight in a rifle scope is the first skill that turns a new rifle into an accurate one.
To sight in a rifle scope, also called zeroing, is to adjust the scope’s internal aiming point until the bullet strikes where the crosshair sits at a chosen distance. That distance is your zero. Once it is set, every shot at that range should land on your point of aim.
A scope does not change where the barrel points. It changes where you look. The sight-in process reconciles the two by moving the reticle with the windage turret for left and right and the elevation turret for up and down until the point of aim and point of impact match. Most hunters choose a 100-yard zero distance because it balances close-range and longer-distance work for common cartridges.
Before anything else, collect a stable rest, the live ammunition you plan to shoot regularly, targets at known distances, a torque wrench in inch-pounds, and eye and ear protection. Shooting from a solid rest removes most of the human error from the process, so your adjustments reflect the rifle and not your wobble.
Mount the scope as low as it sits without touching the barrel. Set your eye relief so you see a full sight picture in a natural shooting position, then level the reticle and torque the rings. A scope that shifts inside the rings will never hold a zero, so this step comes before a single round goes downrange.
Torque matters more than most beginners expect. Most ring screws call for roughly 15 to 25 inch-pounds, applied on dry threads with a real torque wrench and never foot-pounds. Base screws usually take more, often around 45 inch-pounds, depending on the mount. Proper torque keeps the scope from shifting under recoil so it holds zero, and many gunsmiths note that consistent torque matters as much as the exact number. Set eye relief far enough forward that the ocular never touches your brow under recoil.
Bore sighting aligns the barrel and the scope roughly before you fire a shot, which keeps your first rounds on paper and saves ammunition. You can bore sight by looking down the bore on a bolt gun or by using a laser bore sight that fits in the chamber or muzzle.
On a bolt-action rifle, remove the bolt, rest the rifle steadily, and center a 25-yard target through the bore. Without moving the rifle, adjust the reticle until the crosshair sits on that same spot. A laser bore sight does the same job on rifles you cannot see through, like an AR-pattern upper receiver. Bore sighting is a starting point that gets you close, not a finished zero.
Turrets move your point of impact in fixed clicks measured in MOA or MRAD. Knowing your click value tells you how far each click shifts the bullet. One MOA is 1/60th of a degree, which works out to about 1.047 inches at 100 yards, while one mil equals about 3.6 inches at 100 yards.
Turret type | One Click | Movement at 100 Yards | Clicks to Move 1 Inch at 100 Yards |
| 1/4 MOA | 0.25 MOA | about 0.26 inch | 4 |
| 1/10 MRAD | 0.1 mil | about 0.36 inch | About 3 |
The math scales with distance. Divide the distance in yards by 100 to find how many inches one MOA covers there. Closer in, each click covers less, so at 25 yards it takes roughly 16 clicks on a 1/4 MOA turret to move an inch.
Start close, confirm, then stretch. Fire a three-shot group at 25 yards from a stable rest. Adjust the elevation and windage turrets to move the group to center, then confirm at 100 yards. Small groups and patient adjustments beat spraying live ammunition and hoping if you have no shooting experience.
Let the barrel cool between groups. As a barrel heats up, its point of impact can shift, and groups open. In one NRA test, a rifle that put its first three shots into a third of an inch opened to roughly an inch and a half by the fifth shot as the barrel warmed. Cold, unhurried groups give you a zero you can trust in the field.
The fastest way to lose an afternoon is to chase a moving zero. Most sight-in frustration traces back to the setup rather than the shooter or the scope, so rule these out first before you start second-guessing your glass or your ammunition.
A clean zero depends on seeing your target clearly, and that comes down to glass. Bright, high-resolution optics let you read bullet holes at distance, judge light at dawn and dusk, and hold a precise aiming point through the whole sight-in process. This is where your optics system wins.
GPO builds that clarity into every line. The GPO CENTURI pairs zero-stop locking turrets with illuminated reticles for precise dialing, the SPECTRA reaches out with high magnification and convertible ballistic turrets, and the PASSION family stays bright and fast for closer work. For quick target acquisition at close range, a red dot sight simplifies the whole picture. The same GPObright coatings that reach up to 92% light transmission in the scopes carry through the PASSION HD binoculars and RANGEGUIDE rangefinding binoculars you use to confirm distance and spot your hits.
Most shooters zero in 10 to 20 rounds. Bore sighting first gets you on paper, then a few three-shot groups at close range and at your zero distance dial it in. Using one consistent load keeps the round count and the guesswork low to get an accurate shot.
A longer range of a 100-yard zero suits most hunting and range work with common centerfire cartridges. A 25-yard or 50-yard zero is a fast starting point that gets you close, but always confirm the final zero at the distance you actually shoot.
No, but it saves ammunition. Bore sighting only gets you roughly on paper, and you still confirm the zero with live fire. On a bolt gun, you can bore sight by eye, while other actions need a laser bore sight.
They can. Temperature, altitude, and air density all shift a bullet’s arc, so a rifle zeroed in summer heat may print differently in cold weather. Inside 200 yards, the change is usually small, but past your dead-on distance, you may need small elevation adjustments to keep the group centered.
Sighting in a scope is a repeatable skill, not a lucky afternoon. Gather the right gear, mount and torque your scope correctly, bore sight to get on paper, and then work from a 25-yard target out to your zero distance with small, unhurried groups. Let the barrel cool, rule out the setup mistakes that move a zero, and you will walk off the range with a rifle you can trust when it counts.
The one thing that makes every step of that process easier is the glass on top of your rifle. GPO engineers its optics in Germany and prices them for the American shooter, often around 30% below comparable premium brands, and every optic is backed by a fully transferable Spectacular Lifetime Warranty that follows the scope and not just the original owner. GPObright coatings pass up to more than 92% of available light, so your reticle and your target stay sharp from first light to last. You can read more about the company and its former Zeiss leadership on the About GPO USA page.
Browse the full lineup of GPO riflescopes and find the glass built for the way you shoot.
