How To Zero A Deer Rifle Scope For The Best Hunting Accuracy

In a world of precision firearms, accuracy is characterized by; the ability to hit what one is aiming at. If you ask skilled target shooters the question, How to Zero a Deer Rifle Scope for Hunting? Their answer will be the same as experienced hunters perched in a tree-stand.

Zeroing a rifle scope at a pre-determined distance is the same, no matter the application. Divergence from one shooting technique to the other takes place in dozens of small unnoticeable differences.

The height of the shooter, design of the ammo, quality of the reticle, quality of the rings, surroundings all impact hitting the mark.

A perfect aim requires command of what you can control. If your objective is precise accuracy at the firing range or in a tree stand, it can not be understated; start with a quality rifle, scope, and rings.

Whether you are bore sighting or your zero is 500 yards, a shortcoming with any part of the setup results in a miss.

Let’s get started!

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Accuracy Defined

It is fundamental to understand the concept of zero and accuracy. A bullet’s flight path is subject to gravity the moment it leaves the rifle barrel.

The ZERO aligns the scope to intersect with the bullet’s path at a given distance.

A rifle’s zero is the point in which the bullet’s path intersects the line of sight for the second time.

A bullet strikes the line of sight at 25 yards then continues to rise. The bullet begins its descent and intersects the line of sight again at 100 yards, where we have the second zero. There are various factors influencing trajectory once a bullet leaves the barrel.

Zeroing a rifle scope is best characterized as a calibration between scope and rifle. Every shooter has a point of view and best practice on how to zero. Pay attention to remarks prepared by scope and ammo manufacturers.

Results they uphold are at 100 yards in perfect shooting conditions at a closed range, with standard 24- inch barrels.

A popular myth: 25- yard zero will be dead on at 100 yards. Depending on load, caliber, and other factors, POI will be 2.5 to 3 inches high. Start with boresighting.


Which Optic You Use Matters

Rifle scope glass is the heart of an accurate zero. Brands such as Nikon, Vortex, and Nightforce have taken optics and scope technology to exciting new heights.

Companies like Swarovski have used decades of glass fabrication to re-invent scope optics.

Elite shooters know the critical influence of quality equipment. If you are in the field and find you are missing wide- open opportunities, cheap rifles, and scopes play a dominant role.

Are you forced to re-zero before every hunting trip or match? If you are serious about your craft, start with quality equipment.

Please check out: best precision rifle scopes


Zero With Various Calibers

It is a juggling act for shooters to chamber different calibers through a single rifle and be accurate. The trickiest part of this situation, compensating for trajectory differences or bullet drop between each caliber.

The first challenge: what caliber am I going to have my initial zero?

The answer should be: choose the ammunition you employ the most, or maybe a favorite match or target round.

If the rifle provides a dual purpose, such as a defensive and hunting weapon, zero at the defensive load above alternatives.

When shooting anything other than your zeroed ammunition, dealing with countless trajectories is all but impossible. Projectile weights, bullet design, distance, and load differences alter the trajectory path.

Elite shooters are embracing the benefits of advanced reticle design and scope software tailored to the chambered round. Consider Nikon’s Spot-On software and its ballistic match technology.

The BDC reticle works by using a pattern that anticipates how much a projectile will drop at a given range.

Spot-On technology provides precise aiming points extracted from the largest database of factory delivered ammunition in the world. Detailed atmospheric and projected trajectory paths are possible to input. Nikon has taken their Spot-On technology a step further with its custom turrets.

Pair the Nikon turrets with spot-on intelligence, and you have unparalleled accuracy. Scope and ammo builders around the world have fashioned similar technologies. Ballistic reticle and turret technology are heading through the roof.

Sig Sauer
Bushnell Ballistic Charts
Vortex Long Range Ballistics
Hornady Ballistics

There is no substitute for accuracy confirmation except the shooting range. Test out different calibers, note the results and establish your strategy for improving point of aim.

The following methods and concepts will help to achieve an accurate Zero.


High Angle Shooting

high-angle-shooting

Rarely do hunters of any kind have a straight shot on target. They are usually perched in a tree stand or tucked in a blind somewhere on a hill in a prone position.

The best shooting positions are elevated, looking down on trails and feeders. Aiming points for most big game is the area just behind the shoulders. A dead-on shot goes directly through the heart and lungs.

One of the most challenging shots for any hunter is “game running away” Success means putting the bullet where the game will be.

For an example of difficulty consider: a standard 30 30 Winchester with an average load takes 0.3 seconds for the bullet to impact at 200 yards. A whitetail can burst up to 44 mph.

A lightening fast trigger with the deer in the sites will have POI at least 13 to 14 feet behind.

There are two methods for hitting a moving target.

  • Ambush Method: the firearm is aimed ahead of the target along its suspected path. The shot is taken when the game hits the engagement point. ”The shooter’s follow-through should be rock steady and smooth to minimize/eliminate muzzle movement during the shot.”
  • Termed Tracking: keep the reticle ahead of the moving target at the proper lead, until the sight picture is clear, and the trigger is squeezed. “the desired lead is maintained as the bullet exits the muzzle. The shooter should continue to track the target, which will also enable a second shot to be fired on target, if necessary.”

Bullet Drop

Bullet Trajectory Physics

Bullet drop is defined as the vertical distance of the bullet below the axis line of the rifle bore. Every experienced hunter has to deal with this behavior, and excellent hunters have studied and conquered this area of ballistics. Whenever experienced hunters miss a shot, they want to know why.

When the shot is taken, most hunters do not realize how quickly the rate of drop increases past the zero point, usually resulting in a miss. As distance increases, bullet drop becomes exaggerated.

Referenced Business Insider

Another common myth debunked; a bullet hits high if shooting uphill or low if shooting downhill. Gravity exerts extreme influence on the path of a bullet, as well as velocity.

The takeaway from this, bullets hit high, whether shooting up or down.

Good shooters know how to compensate for the angle. There are plenty of gadgets and smartphone apps that tell us the angle of anything.

However, you need to know how angle affects POI. Use a calculation of TBR (true ballistic range), which many modern rangefinders come equipped with.

If you are good at math, you can calculate the cosine of the angle. Multiple the cosine number by actual yardage, and you have the uphill or downhill distance to input into your scope.

When the shooter adjusts windage or elevation, they are turning screws that push against an erector assembly. The assembly consists of the optical lens and reticle (Crosshair)

Learn More: External Ballistic Effects Explained With Pictures


Reticle

ACSS-reticle

Learn More: Best Aiming Reticles For Hunting

The aiming point or crosshair is called a reticle, and in most scopes, it is located in the erector assembly either in front of or behind the magnification lens.

There are thousands of different designs and purposes for this vital part of a scope. Every scope builder has a set of reticles for different purposes and scope models. Nikoplex, fine crosshairs, duplex, heavy duplex, and so on are different reticle designs.

Thicker reticles show up better in dense underbrush and low light situations. Fine crosshairs, on the other hand, are excellent for target and competitive applications.

  • Center dot reticles are intended to draw the eye to the center for quicker targeting
  • Heavy duplex reticles are used in low-light hunting or brushy areas
  • The BDC or ballistic drop compensation reticle is for longer ranges and quick targeting
  • CQB or close quarter battle reticles are intended for low-powered scopes within 100 yards of the target
  • MilDot reticles are used in sniper situations for long-range shooting

NightForce, a premier scope builder, has recently introduced a hunting centric reticle. These aiming points are designed for specific calibers at different velocities.

They are best used for long-range shooting where the wind will be a significant concern. The Velocity 1000 and 600 are intended to be zeroed, then used without any turret adjustments.


Where should you start to zero?

There are two opinions to this question:

  • The manufacturer usually sets the parallax at 100 yards. Some are adjusted at 50 yards, but not many.
  • 100 yards is far enough away to realize any problems with bore alignment.

Pay attention to the parallax and Zero your equipment at the best distance that suits your hunting situation.

If you are a deer hunter and your feeders and trails are 40 to 60 yards out, establish your zero at 40 yards and adjust elevation ½ to 1 inch for greater distances.

For long-range hunting distances, your first Zero should be at 200 yards, if you expect a kill shots between 150 to 300 yards.

Do not overthink distance! Skill, quality of your rifle, and scope all play a meaningful role in identifying the ideal distance for a zero.

If you are restricted to a firing area of 100 yards or less, practice aiming high 2 inches to simulate a 200 yard zero.


Boresighting

Boresighting is one of the many methods used to sight in a rifle scope. The process is a basic pre-aligning of a rifle barrel’s bore axis with a target. Boresighting is a reliable way to align a scope’s reticle or crosshairs with the center of the barrel.

There are laser boresights which can produce a systematic means to zero.

However, understand how to boresight with the naked eye before progressing to a laser.

Check out: Top Laser Boresights

The following are essential steps to the process.

If you are boresighting a bolt action, remove the bolt, with an AR style, remove the upper assembly from the lower assembly. Cradle the barrel on a steady rest, like sandbags or bench rest.

  • Remove the turret covers.
  • Place a target 25 to 100 yards out.
  • Look through the barrel and center the target, EXACTLY!
  • Lock the rifle in position, proceed up to the scope
  • Adjust windage and elevation until the crosshairs are on target
  • Confirm with a shot on target

Learn more about boresighting here.


Zero at 100 Yards

As your respect for the sport increases, so will your equipment. A few of the first items to acquire should be a bench rest and spotting scope.

Assuming the scope is set up properly, and bore-sighted, make sure the firearm is resting firmly on sandbags or your newly acquired bench rest. Place a target 100 yards out and take your first shot.

If the POI lands, take two more for a three-shot grouping. Throw out any flyers.

Measure distance and direction from the exact spot where the bullets impacted, to dead-on. For accuracy reasons, it is necessary to be correct here.

Adjusting a rifle scope for dead on at any distance, is as much about recognition of windage and elevation as it is technique and experience. To gain the maximum benefit of advanced rifle scopes, you must learn how to correct accordingly, and you must know MOA!

Minute of angle

MOA stands for minute of angle, and each click of a scope turret represents ¼ MOA. Minute of angle is an angular measurement, independent of distance.

1 MOA refers to 1/60th degree in a circle. As a reference point at 100 yards, a single MOA is about 1 inch.

In hunting and targeting terms, 1 MOA means you place a group of three shots within 1 inch at 100 yards. Moving a target to 200 yards would equal 2 inches but still represent 1 MOA.

Remember, Minutes of angle is not a linear measurement!

Learn more here: How To Calculate & Adjust MOA


Continue To Make Your Adjustments

Elevation:
Depending on the POI, turn the elevation turret counter-clockwise to bring the point of aim up. If the bullet impacted 1 inch low, make 4 clicks (1/4 MOA is approximately ¼ inch per 100 yards)

Windage:
This adjustment compensates for shifting wind left or right. Typically, once a scope has been zeroed, windage adjustments should rarely be touched.

As your skill develops, hold left or right of the mark to compensate for rapidly changing winds.

Parallax:
Parallax describes a condition where the reticle offsets the focal plane of your target. In a much simpler term, the reticle causes the target to appear as 3D or as an optical illusion.

At shorter distances, parallax is seldom detected. Higher-end scopes now have turrets to correct for the parallax condition.

Verify
The final factor to a successful zero at any range is to shoot another three-shot grouping. These impacts should be much tighter. If you are a competition shooter, a three-shot grouping within one inch is excellent. For a hunter, your three-shot grouping should be withing 2 to 3 inches.

Anything lower and you stand the chance of missing the vital organs of a whitetail and shooting under the animal.
If you are a perfectionist, make additional windage and elevation adjustments.


Recap

The final piece of the puzzle is the actual zeroing process. Start with quality equipment, move onto the various factors affecting accuracy which are ballistics, distance, and trajectory.
Practice, practice, practice!

Greg Brown

Bachelor of Business Admin from The University of Georgia Worked as a firearm professional with COLT under the custom gun shop department for 11 years Rich experience with firearm trade, hunting, and accessories