How to Sight In a Rifle: 100-Yard Zero, 50-Yard Start, and Iron Sights

Sighting in a rifle means adjusting the sights so the bullet lands where you aim at a known distance. That is all a "zero" is: the one distance where point of aim and point of impact meet. Everything else about how the rifle shoots at other distances follows from that one setting and the load you are using.

This guide walks through a single range session for one shooter and one rifle. It covers where to start, how to read groups, which way to turn the turrets, how iron sights differ, and what to write down when you are done. If you are getting ready for your first season, your first deer hunt covers the rest of the preparation.

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What you need before you go

You do not need much, but you need the right pieces:

• The rifle you will hunt with, with the scope or sights already mounted and the mounting screws snug. A loose ring or base will make any amount of adjusting useless. If you are still choosing, see the deer rifle and rifle scopes pages.
• The exact ammunition you plan to hunt with. Different bullet weights and brands can land in different places from the same rifle. Zero with the load you will carry in the woods, and buy enough of that same load to sight in and still have hunting rounds left.
• Targets with a grid, ideally one-inch squares, so you can read how far off a group is without guessing.
• A steady rest. A bench with a front rest and a rear bag is best. Sandbags, a folded jacket over a backpack, or a bipod on a solid surface can work. The goal is to take your wobble out of the test.
• Ear protection and eye protection. Rifle reports are loud enough to cause hearing damage, especially under a covered bench.
• A spotting scope or binoculars to see holes at 100 yards. Walking down to check between groups works too, as long as the range is cold.
• The tool your sights need and a pen.
• A cleaning kit. A small travel cleaning kit is enough to run a dry patch through the bore before you start. Many rifles throw the first shot from a freshly oiled barrel somewhere different, so shoot a fouling shot or two into the berm before you start counting groups.

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Pick a safe place to shoot

Use an established range if you can. A public or club range with a measured 50- and 100-yard line and a proper berm removes most of the guesswork about distance and backstop.

If you are shooting anywhere else, the basics do not change:

• You need a backstop that will stop every bullet, such as a tall dirt bank. Not a tree line, not open field, not a hill you cannot see over.
• Know what is beyond the backstop and to either side.
• Avoid rocks and water that can cause ricochets.
• Check that shooting is allowed where you are. Rules about discharging firearms vary by county, by property, and on public land. Check before you set up.

Measure the distance. If you are not on a marked range, a rangefinder or a tape measure will tell you whether your "hundred yards" is really 85 or 120. A zero at an unknown distance is not much of a zero.

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Step 1: Bore-sight as a starting point, not a zero

Bore-sighting gets you on paper. It does not sight in the rifle.

On a bolt-action rifle, you can often remove the bolt, set the rifle in a rest, and look through the barrel at a target 25 to 50 yards away. Without moving the rifle, adjust the scope until the crosshairs sit on the same spot you see through the bore. Laser bore-sighters do the same job on rifles where you cannot look through the barrel.

Either way, the result is a rough alignment. Barrel harmonics, the bullet's path, and the ammunition all affect where it actually hits. Treat bore-sighting as "close enough to get the first group on the target," then do the real work with live rounds.

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Step 2: Start close, at 25 or 50 yards

A lot of shooters start at 25 or 50 yards, and there are good reasons for it:

• You will hit the paper. If the first group lands six inches off at 50 yards, it is still on the target. At 100 yards the same error could be off the target entirely, and you have no idea which way to adjust.
• Holes are easier to see.
• Wind and your own wobble matter less, so the group tells you more about the sights.

Start at 50 yards, get the group close to your aiming point, then move to 100 for the real zero. Some shooters also use a 50-yard check for rifles that will be shot at shorter distances in thick cover. How close a 50-yard zero runs to a 100-yard zero depends on the cartridge and how high the scope sits above the bore, so do not assume one equals the other. Confirm at the distance you care about.

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Step 3: Shoot groups, not single shots

One shot tells you almost nothing. You might have pulled it, the barrel might have been cold, or the rest might have shifted.

Shoot a group of three, sometimes five, with the same aiming point and the same hold. Then find the center of that group. That center is the number you adjust from, not the location of any one hole.

Good habits while you shoot:

• Same hold every shot. Same cheek position, same shoulder pressure, same grip. Let the rifle rest on the front bag rather than holding it down hard.
• Breathe and press. Settle the crosshairs, let a breath out, and press the trigger straight back without jerking it.
• Let the barrel cool between groups. A hot barrel can walk shots. Hunting rifles with thin barrels are especially sensitive. A few minutes between groups is normal, and on a hot day it may need longer.
• Call your shots. If you know you flinched, say so to yourself and do not adjust off that hole.

If your groups are large and scattered, stop adjusting. The problem may be the rest, your technique, loose mounts, or a rifle that does not like that ammunition. No turret setting fixes a group that will not hold together.

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Step 4: Read the turrets and walk the adjustments

Most hunting scopes have two turrets:

• Elevation (usually on top) moves the point of impact up or down.
• Windage (usually on the right side) moves it left or right.

The turret caps are normally marked with an arrow and a letter: "UP" for elevation, and "R" or "L" for windage. The marking tells you which way the point of impact will move. If your group is three inches left of where you aimed, turn the windage turret in the "R" direction to move the bullets right.

How much does one click move?

Many hunting scopes adjust in 1/4 MOA clicks. One MOA (minute of angle) is about 1.047 inches at 100 yards, so most shooters round it to one inch. That makes a 1/4 MOA click about 1/4 inch at 100 yards, or four clicks per inch.

Not every scope works that way. Some use 1/8 MOA or 1/2 MOA clicks, and some use milliradians (often 0.1 mil per click, which is about 0.36 inch at 100 yards). The value is usually printed on the turret or in the manual. Check yours before you start counting.

At 50 yards, the same click moves the point of impact half as far as it does at 100 yards. A 1/4 MOA click is about 1/8 inch at 50 yards, so you need about twice as many clicks per inch.

Walking it in

1. Shoot a group. Find the center.
2. Measure how far the center is from your aiming point, up/down and left/right, using the grid.
3. Convert inches to clicks for your scope and distance.
4. Make the adjustment. Some scopes do not settle right away. A light tap on the turret housing, or simply firing the next group, usually settles it.
5. Shoot another group at the same aiming point.

Make one correction, shoot, and look again. Do not chase each hole. Expect two or three rounds of adjusting before you are close.

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Iron sights: which way to move them

Open sights work on the same principle as a scope, but adjusting them can feel backwards until you remember the rule.

Rear sight: move it in the direction you want the bullets to go. If you are shooting left, move the rear sight to the right. If you are shooting low, raise the rear sight.

Front sight: move it the opposite way. If you are shooting left, move the front sight to the left. If you are shooting low, a lower front sight raises the point of impact (some rifles do this with a shorter front post or a different blade).

That is the usual convention. Rifles differ, so check the manual. Some rear sights have a stepped elevation ramp and a windage screw. Others need the sight drifted in its dovetail with a brass or nylon punch. Move a dovetail sight in very small amounts; a tiny change at the muzzle end is a big change on paper.

Iron sights also put more of the job on you. A consistent sight picture matters a lot: the same amount of front post showing in the rear notch, centered, with the target sitting on top of the post or covered by it the same way every shot. Many iron-sighted deer rifles are zeroed closer than 100 yards because the shooter's practical range is shorter. Pick a distance that matches how you will hunt, then confirm it.

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Step 5: Confirm on a fresh target

When the group lands where you want it, put up a clean target and shoot one more group without touching the turrets.

The fresh target matters. On a target you have already shot, it is easy to lose track of which holes belong to which group. A clean group on a clean target is your confirmation.

Some shooters also fire one cold-bore shot on a different day, from a cool barrel, since the first shot of the hunt will come from a cold rifle. If it lands with the group, you are in good shape.

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Where should the bullet land at 100 yards?

Many hunters zero dead-on at 100 yards. It is simple, easy to confirm, and works well for the distances most whitetails are shot at. Others zero a little high at 100 so the bullet stays closer to the line of sight farther out.

How far the bullet drops past your zero depends on the cartridge, bullet, velocity, and scope height, so we are not going to publish a drop table here. If you want that information for your setup, check the ammunition maker's published ballistics for your load, then confirm on paper at the distances you expect to shoot. Published numbers are a starting point, just like bore-sighting.

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Step 6: Write down the zero

Before you leave the range, write down:

• The rifle, scope, and mount
• The ammunition: brand, bullet weight, and line
• The zero distance
• The date, temperature, and roughly what the wind was doing
• How many clicks you moved from the bore-sighted setting, if you counted
• Group size at 100 yards

Keep it with the rifle, in the case, or in your phone. Some scopes let you reset the turret cap to zero once you are sighted in. That makes it easy to check later whether anything has moved.

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When to check it again

Re-check the zero:

• Before each season
• After you change ammunition, even to a different bullet weight from the same brand
• After you remove or adjust the scope or mounts
• After the rifle takes a hard knock, falls, or rides around in a truck for a long trip
• After significant cleaning, if you notice the first shots wander

A quick confirmation group is cheap compared with a missed or wounded deer.

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After the range

Once the rifle is zeroed, practice from the positions you will actually use in the woods, such as sitting, kneeling, or braced in a stand or blind. A rifle that shoots well off a bench can shoot a lot worse off your knee. The ultimate whitetail hunting guide covers stand setup, shot selection, and where to aim on a deer once the gear part is settled.

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