Quick Answer
Zeroing a rifle means adjusting your scope so your point of aim matches your point of impact at a chosen distance. In the UK, most target shooters zero at 100 yards. The process involves shooting a group from a supported position, measuring how far the group is from your aim point, then adjusting the scope turrets to move the point of impact onto the target. Expect to use 20-30 rounds and allow the barrel to cool between groups.
What Does It Mean to Zero a Rifle?
When you fire a rifle, the bullet leaves the barrel on a slightly upward trajectory before gravity pulls it down in a curve called the bullet's path. Your scope sits above the barrel, so at the moment of firing, your line of sight and the bullet's path are not parallel - they are on a slight angle. Zeroing is the process of adjusting your scope so these two lines converge at a specific distance.
Once zeroed at, say, 100 yards, your bullet will strike where the crosshairs point at that range. At shorter distances the bullet will be slightly low (rising toward the zero point), and at longer distances it will be increasingly low (having passed through the zero and descended). Understanding this is fundamental to accurate shooting at any range beyond your zero distance.
What Distance Should You Zero At?
For most UK target shooters and stalkers, 100 yards is the standard zero distance. It is a useful all-round choice because it is close enough to confirm quickly, matches common range distances, and gives a predictable drop curve for most calibres at longer ranges.
Some shooters prefer different zeroes depending on their primary use:
- 100 yards - Standard for most UK target and stalking use
- 200 yards - Popular for F-Class and long-range disciplines where point-blank range is less important
- 25 yards initial zero - Used as a starting point before moving to 100 yards, as it brings you close enough to the full zero to avoid wasting ammunition
- 50 yards - Common for rimfire (.22 LR, .17 HMR) given their shorter effective range
For a new setup, starting at 25 yards to get the bullet on paper, then moving to 100 yards to finalise the zero, saves time and ammunition. At 25 yards, a rifle zeroed for 100 yards will typically print slightly low - around 1 to 2 inches depending on your scope height and calibre.
What Equipment Do You Need?
You do not need specialist equipment to zero a rifle, but the right setup makes the process quicker and more reliable.
Essential
- A supported shooting position - a bipod, shooting bag, or bench rest. Human error from an unsupported position makes it impossible to distinguish scope adjustment from shooter wobble.
- A suitable target with a clear aiming point - a 1-inch dot or small bullseye at 100 yards works well
- Enough ammunition - 20 to 30 rounds is realistic; bring more if your initial shots miss the paper entirely
Helpful Additions
- A rear bag to stabilise the stock
- A spotting scope or binoculars to see impacts without walking to the target
- A bore-sighter or laser bore-sighter to get close before firing
- A cleaning kit - worth having if you are going to shoot a lot of rounds in one session
How Do You Zero a Rifle Step by Step?
Step 1 - Check Your Scope Is Mounted Correctly
Before firing, confirm that your scope rings are torqued correctly, the scope is level, and there is adequate eye relief. A scope that is loose or improperly levelled will not hold zero reliably. If you have just fitted a new scope, check all screws are tight after the first few shots as they can bed in slightly.
Step 2 - Bore-Sight If Possible
Remove the bolt and look through the bore from the rear. Align the barrel with the centre of your target, then adjust the scope turrets until the crosshairs are also pointing at the target centre. This puts you in the right area before firing and reduces the chance of your first shots missing the paper entirely at 100 yards.
A laser bore-sighter does the same job without needing to remove the bolt and is useful for semi-auto or lever-action rifles where removing the bolt is awkward.
Step 3 - Fire a Group at 25 Yards
Set your first target at 25 yards. Fire three shots from a stable supported position. Aim at exactly the same point for each shot. Once you have a group, measure how far the centre of the group is from your aim point - both vertically and horizontally. Make scope adjustments to move the point of impact to your aim point.
Most scopes adjust in quarter-MOA (Minute of Angle) clicks. At 100 yards, one MOA equals approximately 1 inch. At 25 yards, one MOA equals approximately one quarter of an inch - so four clicks moves the point of impact roughly one quarter of an inch at 25 yards. Check your scope's click value and do the maths before adjusting.
Step 4 - Confirm at 25 Yards and Move to 100 Yards
Fire another three-shot group to confirm your 25-yard zero is close. Once you are happy, move your target to 100 yards. At this distance, expect your point of impact to be slightly above your aim point on most standard calibres - typically 1 to 2 inches high, depending on scope height above bore and calibre.
Step 5 - Fire a Three-Shot Group at 100 Yards
Fire three shots from the same stable position. Let the barrel cool for a couple of minutes between shots if your barrel heats quickly. Measure where the centre of your group falls relative to your aim point. Adjust the scope turrets to move the point of impact to your aim point.
- Up/Down: Adjust elevation turret (usually top of scope)
- Left/Right: Adjust windage turret (usually right side of scope)
Remember which direction to turn the turret. Most scopes are marked U/D and L/R, and most turrets click in the direction the point of impact moves - turn the elevation turret "Up" and the shots move up.
Step 6 - Fire a Confirmation Group
After adjustments, fire another three-shot group to confirm. Do not be surprised if the group is not perfectly centred on the first confirmation - scope adjustments interact with each other and some fine-tuning is normal. Make small corrections and fire again.
Once your group is centred on the aim point, your rifle is zeroed at 100 yards. Record your scope settings (most turrets have a zero-set function so you can return to zero easily after adjusting for distance).
Why Do My Groups Move Differently to What the Turrets Say?
This is one of the most common frustrations when zeroing. A few causes:
- Scope quality - Budget scopes sometimes do not track accurately. Ten clicks of adjustment may not produce a consistent ten-click movement in point of impact. Testing this (called "tracking" testing) before relying on the scope for serious shooting is worthwhile.
- Barrel heat - A hot barrel shoots differently to a cold one. Always let the barrel cool between groups for an accurate picture of your cold-bore zero.
- Shooter error - Even from a rest, small inconsistencies in hold, trigger technique, or position can scatter shots. Three shots is a minimum group size; five gives a better picture.
- Ammunition consistency - Switching between different lots of the same ammunition can shift your point of impact slightly. Zero with the ammunition you intend to use regularly.
How Do You Know When the Rifle Is Properly Zeroed?
A rifle is zeroed when a consistent three-to-five shot group centres on your intended aim point at your chosen zero distance, from a supported position, with the barrel at a consistent temperature. Ideally, fire two or three confirmation groups before declaring the zero established.
Record your final scope settings and the ammunition used. If you adjust the scope later for a different range or condition, you can return to your recorded zero position.
How Do You Maintain Your Zero?
A well-mounted scope on a quality rifle with a rigid stock should hold zero almost indefinitely under normal use. However, certain events can shift zero:
- Dropping or knocking the rifle heavily
- Removing and refitting the scope
- Removing and refitting a bipod that was overtightened (which can flex the stock)
- Temperature extremes, particularly with plastic stocks
- Changing ammunition
Good practice is to fire a confirmation shot or group whenever you take a rifle out after a long period of storage, after any knock or impact, or when switching to a different ammunition lot. Many target shooters fire a deliberate "cold bore" shot before competition to confirm zero and note any offset.
What Records Should You Keep When Zeroing?
Keeping a basic zeroing log is good practice and aligns with the general record-keeping expected of UK certificate holders. Note the date, ammunition lot number, scope settings, zero distance, group size, and any conditions that might have affected the session (wind, temperature). This gives you a reference if your zero shifts and you need to diagnose why.
Vectis Shooting Log allows you to record shooting session data digitally, including zero records, ammunition used, and range conditions. Having this information in one place makes it easy to spot patterns over time and to demonstrate responsible record-keeping if your shooting records are ever reviewed.
Frequently Asked Questions
How many rounds does it take to zero a rifle?
Most shooters use 20 to 30 rounds to establish a reliable zero, including the initial bore-sighting stage, 25-yard confirmation, and 100-yard groups. If you start well off target, expect to use more. Bringing 50 rounds gives comfortable margin for a first-time zero on a new setup.
Can you zero a rifle without a bench rest?
Technically yes, but it is much harder and slower. Shooting from a bipod prone or over a rolled-up jacket can work, but any inconsistency in your position makes it difficult to distinguish scope error from shooter error. A bench rest or shooting bag is strongly recommended.
How do scope turret clicks work?
Most rifle scopes click in quarter-MOA increments. At 100 yards, one MOA is approximately 1 inch (1.047 inches precisely). So one click moves the point of impact by approximately one quarter of an inch at 100 yards. If your group is 2 inches low, you need approximately 8 clicks of upward elevation adjustment. Some scopes use MRAD (milliradian) clicks - typically 0.1 MRAD per click, which equals 1 cm at 100 metres.
What is MOA and should I use MOA or MRAD?
MOA (Minute of Angle) and MRAD (milliradian) are both angular measurement systems. MOA is more familiar to UK shooters traditionally, but MRAD is increasingly common and maps more naturally to metric measurements. Use whichever system your scope uses and learn to work with it consistently. Mixing MOA adjustments with MRAD corrections causes mistakes.
Does the zero change with different ammunition?
Yes. Different bullet weights, velocities, and ballistic coefficients produce different trajectories. Even the same calibre in different factory loads can shift zero by an inch or more at 100 yards. Always re-confirm your zero when switching ammunition.
How far does a bullet drop past 100 yards?
It depends heavily on calibre and load. As a rough guide for a .308 Winchester with 150-grain bullets at a 100-yard zero: approximately 5 inches low at 200 yards, 18 inches at 300 yards, and 40 inches at 400 yards. Use a ballistic calculator (many are free online) with your specific calibre, bullet, muzzle velocity, and zero distance for accurate figures.
Do I need to re-zero if I fit a moderator?
Usually yes. A moderator adds weight to the barrel, which can change the barrel's harmonics and shift the point of impact, sometimes by a significant amount. Always re-zero with the moderator fitted. If you sometimes shoot with and sometimes without, you will effectively need two zeros - or accept a point of impact shift when changing.
Can I zero on any range in the UK?
You need a range with at least 100 yards of safe backstop. Many Home Office approved ranges have 100-yard or 100-metre bays. You must be a member or have permission to use the range, and you should check that your calibre is permitted on that range. Public land zeroing is not possible in the UK in the way it is in some other countries.
How often should I check my zero?
At minimum, check at the start of each shooting season, after any significant knock or drop, after any scope work or removal, and when switching ammunition lots. Many serious target shooters confirm zero at the start of every session with a deliberate group before moving on to their main practice.
What is a cold bore shot?
A cold bore shot is the first shot fired from a rifle that has been sitting at ambient temperature - the barrel is cold and has not been warmed by previous shots. Many rifles shoot the first cold round slightly differently to subsequent shots because the barrel expands as it heats. Knowing your cold bore offset is important in competition and stalking contexts where the first shot may be the only one that counts.