Quick Answer
To properly zero a rifle scope, start by bore sighting the rifle, fire a three-shot group at a known distance, measure the point of impact relative to your point of aim, adjust the scope accordingly, and repeat until your shots consistently hit the desired zero point. For most hunting rifles, a 100-yard zero remains the most common choice, though some shooters prefer a 50-yard, 200-yard, or Maximum Point Blank Range (MPBR) zero depending on their intended application.
Key Takeaways
- Zeroing aligns your scope's reticle with the rifle's actual point of impact.
- Bore sighting can save time, ammunition, and frustration.
- A stable shooting position is critical for accurate results.
- Most scope adjustments are measured in MOA or MRAD.
- Three- to five-shot groups provide more reliable data than single shots.
- A 100-yard zero remains the most common choice for hunting rifles.
- Environmental conditions, ammunition, and rifle setup can all affect zero.
Why Proper Scope Zeroing Matters
A high-quality rifle and premium optic are only as effective as their zero.
Many shooters spend hundreds or even thousands of dollars on rifles, scopes, mounts, and ammunition, only to rush through the zeroing process. Unfortunately, a poorly zeroed rifle can lead to missed opportunities in the field, frustrating range sessions, and reduced confidence behind the trigger.
Zeroing a scope is the process of aligning the optic so that the bullet impacts where the reticle is aimed at a specific distance. Once properly zeroed, the shooter can make informed elevation and windage adjustments or apply accurate holdovers at longer distances.
Whether you're setting up a hunting rifle, long-range precision rifle, AR-15, or general-purpose firearm, proper zeroing is one of the most important steps in the entire setup process.
What Does "Zeroing a Scope" Mean?
When a rifle is fired, the bullet travels along a trajectory that differs from the line of sight through the scope.
The scope sits above the barrel, which means depending on the chosen zero distance and ballistic trajectory, the bullet's path may intersect the shooter's line of sight one or more times during flight. Zeroing adjusts the optic so that the bullet's impact matches the point of aim at a chosen distance.
For example:
- A 100-yard zero means the bullet impacts at the point of aim at 100 yards.
- A 50-yard zero means the bullet impacts at the point of aim at 50 yards.
- A 200-yard zero means the bullet impacts at the point of aim at 200 yards.
The selected zero distance determines where the bullet intersects the line of sight and influences the amount of holdover or hold-under required at other distances.
Equipment Needed to Zero a Scope
Before heading to the range, gather the necessary equipment.
Essential Items
- Rifle
- Mounted scope
- Appropriate ammunition
- Stable shooting bench
- Front and rear shooting bags or bipod
- Targets with visible aiming points
- Stapler or target stand
- Eye and ear protection
Helpful Accessories
- Bore sighting tool
- Spotting scope
- Laser rangefinder
- Ballistic calculator
- Wind meter
- Notebook for recording data
- Torque wrench or inch-pound driver
Having the right equipment helps eliminate variables and makes the process more efficient.
Step 1: Verify Scope Mounting Hardware
Before firing a single round, ensure the optic is properly installed.
Check:
- Base screws
- Ring screws
- Scope level
- Proper eye relief
- Torque specifications
- Proper ring alignment (when applicable)
Verify base screws are secured with the manufacturer's recommended thread locker (if specified).
Loose rings or improperly torqued mounts are among the most common causes of shifting zeros.
Even a small amount of movement between the scope and rifle can create significant accuracy problems downrange.
Step 2: Bore Sight the Rifle
Bore sighting is not the same as zeroing.
However, it dramatically reduces the amount of ammunition required to achieve a proper zero.
Bore sighting only places the first shots on paper. Final zero must always be confirmed with live ammunition.
Traditional Bore Sighting
For bolt-action rifles:
- Remove the bolt.
- Secure the rifle.
- Look through the bore at a target approximately 25 yards away.
- Center the target in the bore.
- Without moving the rifle, adjust the scope until the reticle aligns with the same target.
Laser Bore Sighting
Laser bore sight tools project a visible reference point that allows the shooter to roughly align the scope before firing.
While not perfectly accurate, they often get the rifle close enough to begin live-fire zeroing.
Step 3: Start at 25 Yards
Large-caliber magnum rifles are often easier to begin at 50 yards because many can print significantly high when zeroed at only 25 yards.
Many shooters begin at either 25 or 50 yards, depending on the rifle, cartridge, and available range facilities.
This allows large adjustments to be made quickly while ensuring rounds are impacting the target.
Set up:
- Stable bench position
- Consistent cheek weld
- Solid support for the rifle
Fire a three-shot group rather than adjusting after every shot.
Single shots can be misleading due to shooter error or ammunition variation.
The goal is to identify the center of the group rather than chase individual impacts.
Step 4: Understand Scope Adjustments
Most modern scopes use either MOA or MRAD adjustments.
MOA Scopes
Most hunting scopes use ¼ MOA adjustments, but some scopes use ½ MOA, ⅛ MOA, or other click values. Always verify your optic's click value before making corrections.
At 100 yards:
- 1 MOA = approximately 1.047 inches
- ¼ MOA = approximately 0.26 inches
At 25 yards:
- ¼ MOA = approximately 0.065 inches
MRAD Scopes
Many tactical and precision scopes use milliradians.
At 100 yards:
- 1 MRAD = approximately 3.6 inches
- 0.1 MRAD = approximately 0.36 inches
Always confirm your scope's adjustment system before making corrections.
Step 5: Adjust the Scope
Measure the center of the group relative to the target's aiming point.
For example:
If the group impacts:
- 2 inches low
- 1 inch right
At 25 yards, calculate the necessary adjustment based on your scope's click value.
With a ¼ MOA scope, each click moves impact approximately 0.065 inches at 25 yards. A group 2 inches low would require roughly 31 clicks up. A group 1 inch right would require roughly 15 clicks left.
Most scopes indicate:
- UP
- DOWN
- LEFT
- RIGHT
on the turrets.
Adjust the optic accordingly and fire another group.
Make only one adjustment between groups whenever possible.
Repeat until impacts are centered.
Step 6: Move to 100 Yards
Once the rifle is roughly zeroed at 25 yards, move to your intended zero distance.
For most shooters, this will be:
- 100 yards for hunting
- 50 yards for some AR-15 applications
- 100 or 200 yards for general-purpose rifles
- Custom distances for long-range rifles
Fire a three- to five-shot group.
Resist the temptation to chase individual impacts. Consistent groups provide far more reliable adjustment data.
Groups provide significantly better data than individual impacts.
Measure the center of the group and make adjustments as necessary.
Continue until the group is centered on the intended point of aim.
Common Zero Distances and Their Uses
50-Yard Zero
Best For:
- AR-15s
- General-purpose defensive carbines where lawful
- General-purpose carbines
Benefits:
- Fast setup
- Practical defensive use
- Common for red dots and LPVOs
36-Yard Zero
Used primarily by some AR shooters seeking a trajectory similar to a 300-yard battle zero.
Popular with some military-style training.
Benefits:
- Flatter trajectory through intermediate distances
100-Yard Zero
Best For:
- Most hunting rifles
- Common choice for bolt-action rifles
- General shooting
- Beginner shooters
Benefits:
- Easy ballistic calculations
- Common ammunition data
- Simple trajectory management
200-Yard Zero
Best For:
- Open-country hunting
- Longer-range applications
Benefits:
- Flatter trajectory
- Reduced holdovers at moderate ranges
Maximum Point Blank Range (MPBR)
MPBR varies significantly depending on cartridge, bullet weight, velocity, and the size of the intended target.
Best For:
- Hunting
Benefits:
- Minimal holdover adjustments
- Increased practical field effectiveness
How Many Shots Are Needed to Zero?
Many shooters waste ammunition during the zeroing process.
A properly mounted scope that has been bore sighted can often be zeroed within:
- 9 to 15 rounds
However, most shooters should plan for:
- 20 to 40 rounds
This allows confirmation groups and verification after adjustments.
Factors That Affect Zero
A rifle can be perfectly zeroed one day and slightly different the next.
Ammunition Changes
Different loads often produce different points of impact.
Changing:
- Bullet weight
- Velocity
- Manufacturer
may require re-zeroing.
Temperature
Extreme temperature shifts can affect:
- Powder burn rate
- Velocity
- Point of impact
Altitude
Higher elevations generally result in less drag and flatter trajectories.
Optic Movement
Loose mounts remain one of the most common causes of shifting zero.
Barrel Fouling
Some rifles shoot differently when clean versus fouled.
Understanding your rifle's behavior helps maintain consistency.
Confirming Your Zero
Many shooters stop after achieving a single centered group.
This is a mistake.
Always confirm your zero.
Fire additional groups to ensure consistency.
A proper confirmation process may include:
- Multiple three-shot groups
- Different shooting positions
- Verification at additional distances
The extra time spent confirming can prevent major issues later.
Common Zeroing Mistakes
Failing to Fire a Cold-Bore Shot
Hunters often fire only one shot in the field.
Knowing where your rifle places the first cold-barrel shot can be just as important as knowing where it groups after several rounds.
Adjusting After Every Shot
Groups tell the real story.
Individual shots do not.
Using Inconsistent Ammunition
Use the same ammunition intended for the rifle's primary purpose.
Rushing the Process
Allow the barrel to cool when necessary.
Heat can affect performance.
Ignoring Fundamentals
Poor trigger control, breathing, and follow-through can create misleading results.
Changing Magnification Without Understanding Scope Type
Shooters using second focal plane (SFP) scopes should understand that holdover marks are typically calibrated for a specific magnification setting.
Not Confirming Zero
A single group is not enough.
Verification matters.
How Often Should You Check Your Zero?
Most experienced shooters verify zero:
- Before hunting season
- After transporting firearms long distances
- After changing optics
- After installing a suppressor
- After changing ammunition
- After hard impacts or drops
- Periodically throughout the year
Even quality optics can occasionally shift due to environmental factors or handling.
Final Thoughts
Learning how to zero a scope is one of the most important skills any rifle shooter can develop.
The process is not complicated, but it requires patience, consistency, and attention to detail. By starting with proper mounting, bore sighting the rifle, shooting accurate groups, and making calculated adjustments, shooters can quickly establish a reliable zero and build confidence in their equipment.
Whether you're setting up a deer rifle, precision rifle, AR-15, or general-purpose firearm, a properly zeroed optic forms the foundation for accurate shooting. Taking the time to do it correctly ensures your rifle performs as intended when it matters most.
Successfully zeroing a scope depends on more than accurate adjustments. A properly installed optic begins with quality mounting hardware that can withstand recoil and maintain alignment over time. If you're still assembling your rifle setup, our guide to choosing the right scope mounts walks through the differences between rings, one-piece mounts, cantilever designs, and other mounting solutions.
Frequently Asked Questions
Should I Zero With the Ammunition I Plan to Hunt or Compete With?
Yes. Even cartridges of the same caliber can produce different points of impact due to differences in bullet weight, velocity, and bullet construction. Always confirm zero using the exact ammunition you intend to use in the field or during competition.
What distance should I zero my rifle scope?
For most hunting rifles, a 100-yard zero remains the most common choice. AR-15 shooters often prefer a 50-yard zero, while some long-range shooters may choose 200 yards or another distance based on their specific needs.
Can I zero a scope without a bore sight?
Yes. Bore sighting simply saves time and ammunition. A rifle can be zeroed using live fire alone.
How many rounds does it take to zero a scope?
Most properly mounted and bore-sighted rifles can be zeroed in approximately 10 to 20 rounds, though additional ammunition is often used for confirmation.
Should I adjust my scope after every shot?
No. Fire three- to five-shot groups and adjust based on the center of the group rather than individual impacts.
What is the best zero for deer hunting?
A 100-yard zero is the most common choice, though many hunters also use a 200-yard zero or MPBR zero depending on cartridge and terrain.
Why does my rifle lose zero?
Common causes include loose scope mounts, ammunition changes, environmental conditions, damaged optics, or shooter-related factors.
About the Author
This article was written by the ProArmory editorial team based on current shooting practices, optics manufacturer guidance, ballistic principles, and practical range experience. The team regularly evaluates rifles, optics, ammunition, and shooting accessories to provide educational, buyer-focused content for responsible firearm owners.
Disclaimer
This article is intended for informational and educational purposes only and should not be considered professional training, gunsmithing, hunting, or shooting instruction. Always follow safe firearm handling practices, use proper eye and ear protection, and comply with all applicable federal, state, and local laws. Ballistic performance and recommended zero distances vary by firearm, cartridge, optic, and intended application. Always confirm your zero using the specific ammunition you intend to use in the field or on the range. Verify all adjustments and firearm setup procedures according to your firearm and optic manufacturer's instructions before use.
