Introduction

Getting your scope zeroed is only half the story. Once you’ve dialled in that first zero, a handful of other factors come into play — ammo consistency, wind, parallax, and the quality of the scope itself. These determine whether that zero actually holds up on the range. If you need the step-by-step process for setting a zero in the first place, see our guide to zeroing your scope and turret adjustment. This guide covers what happens around that process. It looks at what can throw your zero off, what parallax actually is, and what to look for when choosing a scope.

What Can Throw Off Your Zero

Ammo is important because different bullets have different rates of drop, which can influence your point of aim. Hunters should stick to one type of ammo and shoot with that type for all their shots because changing ammo will change your zero. For target shooters, reloading might be worth exploring to tighten the groups. Good premium ammo can also be the solution for a reliably repeatable shot.

Another factor that can affect your zero is the wind. The faster the wind blows, the bigger the deviation and inconsistency in your shooting. That can cause shots to drop, shift sideways, and even lift. Using bullet trajectory tables and charts, or even a Kestrel Ballistic calculator is a good way to compensate for this. But for setting your zero, ideally you don’t want any wind conditions.

You also want to have adequate eye relief on your scope. This will prevent your reticle from hitting you when the weapon recoils. Ensure you have at least 3.5 inches of eye relief on your scope.

Understanding Parallax

Some scopes have a parallax adjustment turret. This is a third turret knob that adjusts for the reticle’s tendency to shift with the movement of your head. It brings the reticle and the sight picture into the same plane. Parallax is usually located on the left or the front of your scope.

Parallax on low-quality scopes can be a serious problem, especially for newer shooters. It can lead to blurry images, missed shots, and just frustration trying to get on target. It’s best to avoid it as much as possible by purchasing a scope with high-quality turrets and decent glass.

Using a Gun Vice Safely

You should always use a gun vice to keep your gun stable during the zeroing process. This will help to reduce the chances of human error and can save you a lot of time, money, and wasted ammo. Use gun vices in a limited fashion, though. The recoil tends to whiplash the rifle and can damage the scope over repeated use.

MOA vs Mil: Which Should You Choose

Both MOA (Minute of Angle) and Mil (Milliradian) are units of measurement derived from the angle of a bullet travelling from the muzzle to a target. Our turret adjustment guide covers the basics of each. Choosing between them comes down to how you like to work.

MOA usually provides a smaller subtension increment than Mil — a 1/4 MOA click is a smaller adjustment than 0.1 Mil. When it comes to small adjustments, you want your point of impact to precisely match your point of aim. 1/4 MOA scopes with repeatable turrets will be your best option there. However, in disciplines like PRS, where rapid calculations are needed under time pressure, Mils are easier to deal with mentally than MOA. With a ballistics calculator, either system is just as easy to read and dial in, especially if you have a HUD that reads it out to you.

Sub-tensions Explained

A scope’s reticle contains subdivisions, or sub-tensions, that help you make accurate adjustments. These are based on the distance you need to move your point of impact up or down a vertical line and left or right a horizontal one.

The best way to zero your scope is to use a bulls-eye target specifically suited for this purpose. These targets have detailed measurements and are typically the most precise you can buy. You can also use a turret-generated elevation click to aid in the zero-setting process. This is a feature on all high-end riflescopes that helps reduce movement during reticle adjustment.

When zeroing a scope, position the rifle as low and stable as possible. The rifle’s movement will affect the sight picture and can lead to missed shots. This is especially true with an expensive, high-magnification riflescope. The erector tube and crosshairs will move around quite a bit as you shift your aim point, so a steady hand matters. Taking the time to set up the reticle correctly pays off in the long run.

Choosing a Quality Scope

Getting a quality scope is a core component of your firearm setup. It must be recoil-tested and able to endure the likes of a 50-cal. It should also resist internal condensation by being nitrogen-filled, and come with a decent set of glass. Element Optics has had a strong track record for air rifles as well as firearms, offering good value for money in both. If you would like to discuss reticle types, scope features, and the application to your rifle type, feel free to reach out to us at the range.