Zeroing Your Rifle

Lesson 10 of 18 · Module 3, lesson 3

Assumes the Hunting Primer. New here? Start there first.

Your objective

By the end, you'll be able to perform the boresight-then-group zeroing process from a bench and record a cold-bore point of impact for your varmint rifle.

Procedure ~9 min

Your rifle has a new scope. You know your cartridge. You drove an hour to the groundhog field. You set up at 200 yards, steady on the bipod, perfect trigger press — and you miss high-right by 8 inches. An unverified zero is not a minor inconvenience. It means wounding an animal or a clean miss on a shot you did everything right on. The zero session is not a formality. It is the thing that makes every calculation between now and the shot honest.

Quick recall

From Optics for Varmints — what does 1/4 MOA per click mean in practice when you are adjusting your scope turrets at 100 yards?

Each click moves the point of impact 1/4 inch at 100 yards Each click moves the reticle 1/4 of the total MOA travel Click value doesn't matter — just fire until the shots are centered

Show answer

Correct: Each click moves the point of impact 1/4 inch at 100 yards — Right. Most hunting and varmint scopes use 1/4 MOA clicks. At 100 yards, 4 clicks = 1 inch of point-of-impact movement. At 200 yards, 4 clicks = 2 inches. This is the math you do to adjust your zero.
Not quite: Each click moves the reticle 1/4 of the total MOA travel — MOA click value means 1/4 minute of angle per click — which equals 1/4 inch at 100 yards, 1/2 inch at 200 yards, and 3/4 inch at 300 yards. It is a measure of angular movement, not a fraction of the total range.
Not quite: Click value doesn't matter — just fire until the shots are centered — Click value is exactly how you translate your measured group error into the number of adjustments you need to make. Without knowing click value, adjusting the zero is pure guesswork.

Step 1 — Boresight to get on paper

Boresighting aligns your scope’s reticle roughly with the bore before you fire a single shot. This puts your first real shot somewhere on a paper target instead of six feet off the berm. It saves ammunition and time.

Two methods:

Bolt-removal / visual boresight: Remove the bolt (bolt-action rifles) and look directly through the barrel. Center a distant target in the bore. Without moving the rifle, adjust the scope’s reticle until it also points at the same spot. This gets you roughly on paper at 25–100 yards.
Magnetic or optical collimator: A tool that inserts into the muzzle and projects a grid. Adjust the scope to align with the collimator’s reference grid. More convenient with a semi-auto that cannot be bolt-removed for a visual.

Boresighting is approximate. A visual boresight gets you within a few inches at 25 yards, which is all you need to find the target on paper. Do not zero off a boresight; shoot a real group.

The why Why the first shot off a cold clean bore matters most

A barrel heated from multiple shots has slightly different dimensions than a cold barrel. The first shot from a clean, room-temperature barrel — the “cold-bore shot” — often prints slightly differently from a warmed barrel. In hunting, you almost always shoot a cold, clean rifle. A zero confirmed only from a warm barrel after 10 shots may put your hunting shot an inch or two off. Record the cold-bore hit separately and, if it consistently prints differently from your group center, zero to the cold-bore location.

Step 2 — Set up a stable bench

The goal of zeroing is to eliminate human wobble from the equation so you can see what the rifle and ammunition actually do. A bench is the right tool for this.

Rest the forestock on a front bag or bipod, never the barrel (contact with the barrel deflects it and shifts point of impact)
Support the buttstock’s toe on a rear bag or rest so the rifle holds steady without your muscle tension
Natural point of aim: the rifle should be aimed at the target before you touch the trigger — not held on by force. Shift the entire rest until that is true
Cheek weld: consistent head position on the stock produces consistent eye position in the scope; every shot should look the same through the glass

Step 3 — First shots at 25 yards

Start at 25 yards if available. At this short distance you can confirm the boresight is close and see impacts without walking to the target repeatedly. Fire 2–3 shots from the stable bench. The group should be within a few inches of center. If it is more than 6 inches off, re-check rings and boresight before proceeding.

Move to 50 yards for the next group. A 50-yard initial zero is useful for rimfires (.22 LR, .22 WMR) whose arc maxes out around that range. For centerfires, 50 yards is a clean waypoint — a group centered at 50 yards is typically a useful launching point for finishing the zero at 100 or 200.

Step 4 — The 100-yard group and adjustment

Fire a 3-shot group from a stable bench rest. Let the barrel cool 2–3 minutes between shots if you are shooting a hot centerfire. Aim at the exact same point for every shot.

Read the group — center, not fliers. Draw an imaginary triangle or circle that encloses all three holes. The center of that shape is your group center. Ignore the one shot that felt weird; it is still data, but a single outlier does not redefine the zero.

Measure the error:

How many inches is the group center from your point of aim?
Which direction: high, low, left, right?

Calculate clicks needed:

At 100 yards, 1/4 MOA scope = 1/4 inch per click
Group is 3 inches low? You need 12 clicks UP on the elevation turret
Group is 1.5 inches right? You need 6 clicks LEFT on the windage turret

Make the adjustments and shoot another group. Repeat until the group center sits on your intended aim point.

Deep dive Choosing your zero distance: 100-yard or 200-yard zero?

For a .223 or .22-250, a 200-yard zero is practical for Piedmont groundhog hunting because most shots fall between 100 and 250 yards. A 200-yard zero means the bullet is slightly high at 100 yards (about 1–2 inches on a .223), on at 200, and drops predictably beyond. You only need to dial in or hold over for shots notably beyond 200. A 100-yard zero is simpler to confirm but means more holdover at 200 and beyond.

For rimfires, a 50-yard zero is common: the bullet is on at 50, only slightly high or flat to 75 yards, and drops hard after that. There is little benefit in zeroing a .22 LR at 100 yards when its practical range ends there anyway.

The zeroing procedure (visual walkthrough)

Diagram showing a four-step zeroing sequence: (1) boresight the rifle, (2) fire a cold-bore shot and mark it, (3) shoot a 3-shot group at 100 yards and measure to group center, (4) adjust turrets and verify with a final group. — Diagram (not a photo). The zeroing loop: boresight → cold-bore shot → 3-shot group → measure error → calculate clicks → adjust → verify. The cold-bore shot is marked separately because it is what matters in the field.

Worked example: reading and adjusting a group

Here is a real zero session, step by step.

Decision

You fire a 3-shot group at 100 yards. The group center lands 2 inches low and 1 inch right of your aim point. Your scope adjusts in 1/4 MOA clicks. How many clicks do you dial, and in which directions?

8 clicks UP on elevation; 4 clicks LEFT on windage

Exactly right. 2 inches low at 100 yards = 8 quarter-MOA clicks up. 1 inch right = 4 clicks left. Adjust, then shoot a verification group. The math is the whole game.

8 clicks DOWN on elevation; 4 clicks RIGHT on windage

Turret directions are: to move the point of impact UP, dial the elevation turret UP. To move it LEFT, dial windage LEFT. Moving it the wrong way doubles the error instead of halving it. Adjust in the same direction you want the group to move.

2 clicks UP; 1 click LEFT — one click per inch

At 100 yards with 1/4 MOA clicks, one click moves impact 1/4 inch — not 1 inch. You need 4 clicks per inch. The group would still be off by 1.5 inches after this adjustment.

Step 5 — Record the cold-bore point of impact

After your group is zeroed, unload the rifle and let it cool completely — at least 15 minutes. Fire a single shot from a cold, clean barrel: this is your cold-bore shot. Mark exactly where it hits relative to your group center.

If the cold-bore shot is within 1/2 inch of the group center, your hunting zero is the group center. If it is consistently 1–2 inches off (common with some heavy barrels and slow-burning powders), consider zeroing to the cold-bore location instead — because that is the shot that counts in the field.

Write it down: distance, ammunition, date, weather conditions, and the cold-bore point of impact. Keep this record with the rifle or in your hunting notes. Zeros shift over time from cleaning, temperature changes, and normal use. A written record tells you when something has changed.

Check the procedure

Knowledge check

You have a 3-shot group centered 3 inches left and 2 inches high of your aim point at 100 yards. Your scope uses 1/4 MOA clicks. Which adjustments do you make?

12 clicks RIGHT on windage, 8 clicks DOWN on elevation 3 clicks RIGHT on windage, 2 clicks DOWN on elevation 12 clicks LEFT on windage, 8 clicks UP on elevation

Show answer

Correct: 12 clicks RIGHT on windage, 8 clicks DOWN on elevation — Right. 3 inches left at 100 yards = 12 quarter-inch clicks right to move the group right. 2 inches high = 8 clicks down. Always move impact in the direction it needs to go: right to move a left group, down to move a high group.
Not quite: 3 clicks RIGHT on windage, 2 clicks DOWN on elevation — You need 4 clicks per inch at 100 yards (1/4 MOA per click). 3 inches = 12 clicks, not 3. 2 inches = 8 clicks. One click moves impact 1/4 inch, not 1 inch.
Not quite: 12 clicks LEFT on windage, 8 clicks UP on elevation — That would move the group even further left and higher — making the error twice as large. To move a left group to the right, turn windage RIGHT. To move a high group down, turn elevation DOWN.

Knowledge check

Why should you record a cold-bore point of impact separately from your group center?

Because the first shot from a cold clean barrel often hits differently than shots from a warm barrel — and hunting almost always means a cold barrel To check if the scope is correctly mounted — a cold-bore shot confirms the rings are tight Cold-bore shots are irrelevant — groups are what matter for hunting

Show answer

Correct: Because the first shot from a cold clean barrel often hits differently than shots from a warm barrel — and hunting almost always means a cold barrel — Exactly. A warm barrel expands slightly and prints shots differently. In hunting you fire one cold shot. If your zero was built from a warm-barrel group and the cold-bore consistently hits 1.5 inches off, you are starting every hunting shot with a known error.
Not quite: To check if the scope is correctly mounted — a cold-bore shot confirms the rings are tight — Loose rings will shift zero, but you check ring torque before any shooting. Cold-bore tracking is specifically about the difference between a cold barrel's first shot and the group center from a warm session.
Not quite: Cold-bore shots are irrelevant — groups are what matter for hunting — Groups tell you the rifle's mechanical precision. The cold-bore shot tells you where that precision is centered when the conditions match what you'll actually have in the field. Both pieces matter.

Take it to the range

This checklist walks you through a complete zero session. Complete it in order — each step depends on the one before.

Sources

Zeroing a rifle scope at 100 yards (step-by-step): https://scopetactics.com/how-to-zero-a-rifle-scope-at-100-yards
Boresighting and zeroing procedure: https://soflete.com/blogs/die-living/long-range-101-zeroing-and-boresighting-a-rifle
How to zero a rifle scope (step-by-step guide): https://huntersloadout.com/blog/how-to-zero-a-rifle-scope
Cold-bore accuracy discussion: https://www.longrangehunting.com/threads/cold-bore-accuracy.250652/
Sighting in your rifle (Texas Parks and Wildlife, applicable fundamentals): https://tpwd.texas.gov/education/hunter-education/online-course/shooting-skills/sighting-in
SCDNR hunting licenses and regulations (verify current requirements before hunting): https://dnr.sc.gov/regulations.html

If you remember nothing else

Boresighting gets you on paper at 25–50 yards without wasting ammunition — it does not replace a real zero.
Shoot groups of 3–5 shots from a stable bench; measure the group center, not an individual bullet hole.
Adjust turrets to move your group center to point of aim — read the scope's click values (usually 1/4 MOA per click at 100 yards).
Verify at your intended zero distance (commonly 100 or 200 yards) after all adjustments.
Your first cold-bore shot matters most in hunting — record it separately, not just the group average.

How ready do you feel?

How ready are you to go to the range, boresight your varmint rifle, shoot a group, make adjustments, and confirm a reliable zero before your first groundhog hunt?

Before you go — a quick look back

Distributed practice: one fast recall from an earlier lesson keeps it from fading.

Quick recall

From Optics for Varmints — why does adjustable parallax matter for the zeroing process, and at what distance should you set it?

Show me the answer

Show answer

Correct: Show me the answer — Parallax error moves the reticle relative to the target when your eye is off-center. When zeroing at a specific distance, set parallax to that distance first — otherwise your group location depends partly on exact eye position, and the zero is inconsistent. Set parallax to your zero distance before shooting any group.

Done with this lesson?

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Step 1 — Boresight to get on paper

Step 2 — Set up a stable bench

Step 3 — First shots at 25 yards

Step 4 — The 100-yard group and adjustment

The zeroing procedure (visual walkthrough)

Worked example: reading and adjusting a group

Step 5 — Record the cold-bore point of impact

Check the procedure

Take it to the range

Complete zero session checklist

Sources

If you remember nothing else

How ready do you feel?

Before you go — a quick look back

Done with this lesson?