Ever wondered what the longest confirmed sniper kill in history was? The title goes to an unnamed soldier serving under the Canadian Armed Forces. In 2002, they took out an insurgent at a distance of just over 2 miles.
To be clear, a shot at that distance requires the best military training the world has to offer. It’s more than rifle aim; there is a ton of physics to account for. None of it would be possible, though, without a rifle scope.
Want to learn how to adjust a scope on a rifle? You’ve come to the right place. Join us for the ultimate guide on lining up your sights for optimal rifle accuracy.
Forces that Act upon a Bullet
Before we dispense any wisdom, it’s key to understand some physics. You see, many people have the false perception that bullets travel in a straight line.
At the range, this perception seems to hold true. The bullet lands about where you aim it at short distances, say 25 yards or less.
At longer distances, the effects of physics are far more noticeable. A host of factors exert themselves on a bullet in flight, as they might an airplane.
Right out of the gate, the recoil of a weapon is the first thing to spoil your rifle aim. Some types of rifles have virtually no recoil, such as a .22. Others, like a Tac-50, could dislocate your shoulder–hugely affecting aim.
The speed, weight, and other characteristics of a bullet decide how fast and far it goes. This includes the shape of the projectile, the grain of the gunpowder, and the pressure of the firearm in question.
Gravity makes everything return to Mother Earth, even a tiny bullet. Bullets don’t travel in a straight line, they travel in a parabola. That is, a curved-down trajectory as gravity pulls them off a straight path.
Wind Speed and Direction
Yes, a blustery day can easily blow a bullet off its trajectory. Even a light breeze. If you plan to shoot at a longer range, rifle accuracy will suffer in different weather.
Air resistance also takes part in this equation. The bullet has to push the air ahead of it out of the way, which slows it down. It loses lethality and impact at long ranges–important if you are hunting.
Simply put, the Coriolis effect is how the Earth rotates beneath objects not attached to it. This affects a bullet, although only at very distant ranges. By the time the bullet has reached the target, the target has moved slightly with the Earth’s spin.
How to Adjust a Scope on a Rifle
So, now you’ve got a better understanding of how physics and bullets interact. It’s time to put them into practice with your scope.
1. Mounting Your Scope
You cannot simply bolt your scope down to the rifle. It has to be in perfect alignment with the barrel, level with it, and sighted for the weapon. This requires careful, minute adjustments and a bubble leveler–or ideally, a dedicated scope leveling kit.
Mounting a scope is doable on your own, but requires an entirely different article. We highly recommend visiting a gunsmith for it unless you like a proper challenge.
Test Your Rifle for the Following
With that said, make sure to check a few things. First, ensure you see through the “eye box.” That is, when you have the rifle shouldered and you are looking down the barrel, make sure you see clearly through the scope.
You also want the perfect height for the scope. Too high, and your cheek won’t rest comfortably against the frame of the gun. Too low, and you won’t be in alignment with the eye box.
“Eye relief” refers to how comfortably your eye sits against the scope. Too close, and the recoil could give you a black eye–known as “scope bite.”
Too far, and you will have to strain your eyes to aim properly. You’re more likely to lose eye box alignment, as well, and suffer parallax decay.
2. Learning Scope Components
Let’s do a quick crash course in scope components. With enough practice, you will hopefully know these parts by heart.
Objective and Ocular Lenses
There are two lenses on a scope: the front and the back. The front lens, pointing out with the barrel, is the ocular lens. The one you rest your eye against near the stock is the objective lens.
The ocular lens usually includes an eyepiece focus. You’ll see you shortly what you need it for.
Elevation and Windage Turrets
The “turrets” are those two adjustable knobs above the scope’s mount. The elevation turret, as you can imagine, accounts for elevation by raising the scope. At longer distances, you will adjust this turret to ensure the crosshairs zero at the correct distance.
The windage turret accounts for wind through lateral adjustment. In other words, turning your scope left or right.
Both adjustments allow you to move the scope precisely in any direction. They’ll become your best friends, especially if you are frequently changing range.
Behind the ocular lens sits a ring knob: the magnification. Twisting it left reduces magnification, increasing your field of view. Twisting it right increases magnification, giving you closer visibility of your target.
3. Focusing the Eyepiece
Focusing the eyepiece means adjusting the scope’s lens correction for an individual shooter. This is a one-time adjustment unless others will be shooting your rifle. If focused properly, the reticle (also known as “crosshairs”) shouldn’t be blurry.
Focusing is pretty easy: simply twist the ocular lens all the way in one direction. Then, while observing through the scope, twist it back until you get a clear, sharp image. Ideally, you should do this on a sunny day with excellent visibility.
4. Zeroing Your Scope
This is where the fun begins. “Zeroing” refers to the process of lining up the scope precisely with the distance of the target. Once the zeroing is done, you can begin shooting.
As we’ve discussed, gravity and other forces will affect the trajectory of a bullet. To account for this, the scope reticles move depending on distance and other factors. Zeroing a rifle to a specific range tells you exactly where the bullet should land between crosshairs.
Using Reticle Hashed Lines
The hashed lines refer to those series of lines beneath the main crosshairs. These help to account for bullet drop that occurs the further from a target you are.
They’re a handy guide to line up shots if you suddenly change the distance to hit another target. At consistent ranges, for more shots, you’ll want to adjust the following below.
Remember, the elevation turret is the top knob on the scope. If you know the exact distance your target is from you (such as stationary blanks at a range) then you can twist the turret to that setting. If not, you’ll need a laser rangefinder or some simple experimentation.
Elevation adjustments are measured in MOA, or “minute of angle.” The minute in the name refers to a clockface’s minute hand and accounts for 1/60th of a degree. In practical terms, this is one inch of travel vertically or horizontally.
Therefore, each click of the turret should adjust your scope by about 0.25 MOA per 100 yards. It’s not exactly one inch, but that’s a distinction that only matters if you take part in competition shooting.
Simply put, you are raising or lowering the reticle until it matches where the bullet lands. You can sit there at the range, shoot a round, then manually adjust the reticle to line up with the impact site.
Using the windage turret is rare, even for seasoned shooters. The problem is with the wind. Wind tends to be sporadic, changing direction and speed very frequently.
Even on a windy day, the windage knob may not be necessary. By the time you account for wind speed and direction, it has likely already changed.
Instead, practiced marksmen typically get a “feel” for the wind. They might rely on the movement of nearby flags, or they might feel it pass by their body. When you’re shooting, you can get a sense for how the wind is misaligning your shots and then account for it.
Adjusting for Parallax
Parallax is the difference between the perspective of your left and right eye. Unfortunately, low-budget scopes do not usually feature parallax compensation/adjustment. If you do have one, it comes as a knob that you can twist.
Magnification is pretty straightforward: to get a closer look, zoom in by twisting right. Zoom out with the opposite movement. This will obviously change with range, like elevation.
Take Courses at Texas Gun Club
Now you know how to adjust a scope on a rifle. It’s tricky business, but a great chance to appreciate the peerless skills required to land long-range shots. Anyone can get familiar with using and zeroing a scope given enough practice.
Texas Gun Club has everything you need in one place: a range, gun safety courses, and special events. Consider joining the club to take advantage of free or discounted fees.