How to Zero a Rifle Scope

Every zeroing guide tells you to adjust and confirm. None of them tell you that the bill arrives in cartridges — so here is the procedure alongside the live cost of the rounds it consumes.

AmmoSpotter Research Desk By AmmoSpotter Research Desk
Published 8 min read
How to Zero a Rifle Scope

What a zero actually is

Your sight line is straight. The bullet's path is not — it leaves the bore below the optic, climbs across the line of sight, arcs over, and crosses back down. A zero is the distance at which the descending path intersects the sight line, which means every zero has a second, closer crossing on the way up.

That geometry is why the question "what distance should I zero at?" has different answers for different rifles rather than one correct one:

  • Rimfire: 25 to 50 yards. The trajectory is steep and short; there is nothing to gain from a distant zero.
  • General-purpose carbine: 50 yards is the common convention, because for typical 5.56 loads the path stays within a few inches of the sight line out to a few hundred yards. Confirm the second crossing with your own load's published trajectory data rather than assuming it.
  • Hunting and precision rifle: 100 yards, because it is the distance every ballistic table, turret marking and drop chart is referenced from.

Pick the distance before you start. Changing your mind halfway through is how a twelve-round job becomes a forty-round job.

Everything you should fix before the first shot

This is where the money is saved, because every mechanical fault here is eventually paid for in ammunition.

Torque the mounting system. Base screws and ring caps have manufacturer torque specs for a reason. A ring cap that is finger-tight will shift under recoil and move your zero after you have paid to establish it.

Check the cant on your base. A 20 MOA canted rail can push a short-range rifle past the bottom of its elevation travel so that a close zero is physically unreachable — you will burn a box of ammunition discovering a problem that is a hardware mismatch. We covered which bases are canted and why in MOA vs MRAD explained.

Level the reticle to the rifle, not to the world. A tilted reticle costs you nothing at your zero distance and progressively more as you dial up, because your elevation correction is no longer purely vertical.

Set the diopter and the parallax. Focus the reticle against a blank background first, then set the side-focus or adjustable objective for your target distance. Parallax error moves your apparent point of aim when your head shifts — which looks exactly like a rifle that will not hold zero.

Build a stable platform. A rest that lets the rifle move is not a rest. You are trying to measure the rifle's behaviour, and anything that adds dispersion means more rounds to see through the noise.

Rests, Bipods and Adapters — Cheapest Live Listings

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One warning about reading that grid: price-sorted, the rest category leads with bipod studs and rail adapters rather than complete rests, because the parts are cheaper than the products. Read the titles. The same caution applies to anything you price-sort in a parts-heavy category.

Use a target with a grid on it. A sight-in target with a measured grid turns "a bit low and left" into a number you can convert directly into clicks, which saves at least one confirming group.

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Bore sight first — it is the cheapest round count you will ever buy

Bore sighting gets the optic roughly aligned with the barrel before you fire anything, either optically through the bore, with a laser cartridge, or with a universal bore sighter clamped to the muzzle.

It does not produce a zero. It removes the stage where you are shooting into a blank backstop trying to find paper, and that stage is where most of the ammunition goes.

Lasers and Bore Sighters — Live Prices

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Note what that grid actually contains: price-sorted, the laser category opens with pressure switches and pistol lasers, and the universal bore sighters appear further up the list. That is a category labelling artifact, not a bargain. Filter by title, not by position.

A bore sighter is a one-time cost in roughly the same range as a couple of boxes of centerfire ammunition. The ammunition it saves is recurring. If you own more than one scoped rifle, the arithmetic is not close.

How many rounds does zeroing actually take?

Here is a realistic budget rather than a best case. These are planning figures for the procedure below, not measurements.

ApproachRounds to plan for
Bore-sighted, 3-shot groups, confirm once9 – 12
No bore sight, find paper at 25 yd then move to 10020 – 40
Precision rifle: 5-shot groups, confirm, verify the dial tracks40 – 60
Adding a second confirmed distance+5 – 10

The procedure that produces the low number:

  1. Fire a three-shot group at your chosen distance from a stable rest, taking your time. Let the barrel cool.
  2. Measure from the centre of the group to the point of aim, horizontally and vertically. Not from the nearest shot. Not from the best shot.
  3. Convert to clicks and adjust once. A quarter-MOA turret moves about 0.26 inches per click at 100 yards; a tenth-MRAD turret about 0.36 inches. Halve the distance for a 50-yard zero, quarter it for 25.
  4. Fire a confirming group. If it is centred, you are done. If it is not, you have information about your rest or your technique, not about your scope.
  5. Confirm at a second distance if the rifle will be shot past its zero.

The expensive mistake at step two is adjusting off a single shot. One shot tells you almost nothing about where the rifle is pointed, and chasing individual holes around a target is the single most reliable way to turn a box of ammunition into a worse zero than you started with. If your round count is running high, it is almost always this.

What zeroing costs, cartridge by cartridge

This is the part the other guides skip. The procedure above is identical across rifles; the bill is not.

5.56 NATO & .223 Remington Price Index

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Market floor / round
$0.450
Market average
$1.053
Lowest box price
$6.99
30-day trend
▲ 1.4%
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.308 Winchester Price Index

Live · Oct 1, 2026
Market floor / round
$0.650
Market average
$1.967
Lowest box price
$11.99
30-day trend
▲ 2.2%
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Take the market floor in the blocks above and multiply by the round count you are planning for. A bore-sighted twelve-round zero on a 5.56 carbine is a trivial expense at today's floor. The same twelve rounds in .308 Winchester costs about half again as much per round, and in 6.5 Creedmoor or .30-06 Springfield roughly double. A precision rifle zeroed properly on five-shot groups, in a cartridge with a floor near a dollar, is a genuine purchase rather than an afterthought.

Run your own numbers rather than trusting a round figure:

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Your true cost per round
$0.500

There is a second cost that is easy to miss: you should be zeroing with the ammunition you will actually shoot. Bullet weight and velocity change where the bullet leaves the barrel and where it lands, and two loads in the same cartridge can print well apart at 100 yards. That means your zeroing rounds come out of your good ammunition, at the good ammunition's price — not out of the cheapest steel-case case on the shelf. How we rank ammunition explains why we treat those as different products rather than interchangeable ones.

If you are buying the rounds for the job, the cheapest way to do it is by the case:

Bulk 5.56 and .223 by Cost Per Round — Live

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For which loads belong in a zeroing session versus a hunting magazine, best 5.56 and .223 ammo splits the practice tier from the precision tier. The whole live market by cost per round sits on the 5.56 and .223 page. And if you are ordering a case rather than buying locally, check ammo shipping restrictions before you check out — the rules vary by destination and change, so verify for your own address.

Zero a rimfire first if you want the skill for almost nothing

The process — read a group, measure, convert, adjust once, confirm — is identical regardless of cartridge. The cost of practising it is not.

.22 LR Price Index

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Market floor / round
$0.058
Market average
$0.162
Lowest box price
$2.99
30-day trend
▲ 1.9%
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Compare that floor to the 5.56 block above: .22 LR runs at roughly an eighth of the cost per round. You can run the full procedure five times on a rimfire for less than one careful centerfire session, and the muscle memory for reading groups and trusting your corrections transfers completely.

What does not transfer is the dope. A rimfire trajectory is far steeper, so the elevation numbers you learn are specific to that rifle. Practise the method on the cheap gun; establish the zero on the real one.

Bulk .22 LR by Cost Per Round — Live

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best .22 LR ammo covers which bulk packs are consistent enough to be worth grouping with — a relevant caveat, because bulk rimfire dispersion can be mistaken for a scope problem.

The mistakes that each cost you a box

  • Adjusting off single shots. Covered above, and worth repeating, because it is the most expensive habit in this article.
  • Untorqued rings. You will establish a zero and then lose it, and pay twice.
  • Wind you did not account for. A mild crosswind at 100 yards will move your group enough to chase. Zero in calm conditions or accept the error.
  • Parallax left at the wrong setting. Produces apparent inconsistency that looks like a rifle fault.
  • Switching ammunition mid-session. Now you have two datasets and no zero.
  • A hot barrel. See above. The group tightens or walks and you learn nothing you can use cold.
  • Assuming a 25-yard zero scales cleanly to 100. It gets you on paper. It does not finish the job.

Most of these are not optics problems, which is the point. If you want to understand why a correction that works at 100 yards does not hold at 400, the answer is in the load's velocity and how fast it bleeds off — muzzle energy versus muzzle velocity is the piece that unpacks it. If you are still choosing the optic rather than zeroing one, start with red dot versus LPVO, and if you are budgeting the practice that follows the zero, how many rounds it takes to get good has the volumes.

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Frequently Asked Questions

How many rounds does it take to zero a rifle scope?+
With the rifle bore-sighted first, budget nine to twelve rounds: a three-shot group to see where you are, one adjustment, a confirming group, and a couple of spare rounds. Without bore sighting, plan on twenty to forty while you find paper. A precision rifle zeroed on five-shot groups and confirmed at a second distance can run past fifty.
Should I zero at 25, 50 or 100 yards?+
Match the distance to what the rifle does. A rimfire is usually zeroed at 25 to 50 yards, a general-purpose carbine at 50 yards, and a hunting or precision rifle at 100. Twenty-five yards is useful as a cheap first step to get on paper regardless, because corrections at close range are large and obvious — then move back and confirm at your real zero distance.
Does bore sighting actually save money?+
Yes, and it is the clearest cost saving in the whole process. A universal bore sighter is a one-time purchase in the same range as a couple of boxes of centerfire ammunition, and it typically removes the entire first stage of chasing shots onto paper. If you zero more than two rifles, it pays for itself in cartridges.
Do I need to zero again if I change ammunition?+
Assume yes. Different bullet weights and velocities leave the barrel on different paths, and two loads in the same cartridge can print meaningfully apart at 100 yards. Zero with the ammunition you intend to shoot — a cheap steel-case practice zero does not reliably transfer to a hunting or match load.
Why does my rifle shoot differently after the first shot?+
Barrels move as they heat, and the first shot from a cold, clean barrel often lands away from the group that follows. For a hunting rifle the cold-bore shot is the one that matters, so confirm it separately and let the barrel cool between groups rather than firing ten rounds in a row and averaging the result.
Can I zero a rifle at an indoor 25-yard range?+
You can get on paper and verify that your scope tracks, which is genuinely useful. You cannot establish a 100-yard zero from 25 yards by arithmetic alone with any real confidence, because small angular errors at close range become large ones at distance. Treat the indoor session as stage one and finish outdoors.
Topics .22 LR .223 / 5.56 NATO Cost Per Round Optics Training & Practice

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