Getting your shots to land exactly where you aim is the goal of every shooter. One key to achieving that precision is knowing how to adjust parallax on rifle scope. This adjustment is often misunderstood, but it’s a crucial skill for improving your accuracy at varying distances.
Parallax error occurs when the target image does not fall precisely on the reticle’s focal plane. In simpler terms, if your eye moves slightly off-center behind the scope, the reticle appears to shift on the target. This can cause aiming errors, especially at longer ranges. By adjusting the parallax, you make the target and reticle appear on the same optical plane, removing that error and giving you a clearer, more accurate sight picture.
How to Adjust Parallax on Rifle Scope
The process for adjusting parallax depends on the type of adjustment system your scope has. Most modern rifle scopes use one of three common methods: a side focus knob, an adjustable objective (AO) lens at the front, or a fixed parallax setting. Let’s break down how to handle each one.
Understanding Your Scope’s Adjustment System
First, you need to identify what you’re working with. Look at your scope.
* Side Focus Knob: This is a knob on the left side of the scope’s main tube, usually labeled “SF,” “P,” or with distance markings. It’s the most common system on mid-to-high-end scopes.
* Adjustable Objective (AO): This is a ring on the front bell (objective lens end) of the scope that you rotate. It’s also marked with distance yardages.
* Fixed Parallax: Many budget or hunting scopes set for a specific range (like 100 yards) have no external adjustment. You cannot adjust parallax on these; you must learn to maintain a consistent cheek weld.
Step-by-Step Adjustment Process
Once you’ve identified your adjustment type, follow these general steps. You’ll need a stable rifle rest and a target at a known distance.
1. Secure Your Rifle and Target
Place your rifle solidly in a rest or on sandbags so it is absolutely stationary and aimed at your target. The target should be at a specific distance you know, like 100, 200, or 300 yards. This is critical because you cannot adjust correctly if the rifle is moving.
2. Look Through the Scope
Get into your normal shooting position behind the scope. Now, deliberately move your head slightly up and down and side to side. Watch the relationship between the reticle and the target. If the reticle appears to move across the target as you move your head, parallax is present and needs to be corrected.
3. Adjust the Knob or Ring
While keeping the rifle steady and continuing to look through the scope, slowly rotate your side focus knob or AO ring. As you adjust, keep making small head movements. Your goal is to find the point where the reticle stops moving relative to the target. When the reticle stays on the same point on the target despite your head movement, parallax is eliminated.
4. Fine-Tune for Clarity
Parallax adjustment is also a focus adjustment. The image should become sharp and clear when parallax is removed. Fine-tune the knob until the target is in its clearest focus. Don’t use the eyepiece diopter for this; that’s only for focusing the reticle itself.
Tips for Different Shooting Scenarios
* Long-Range Precision: For targets beyond 300 yards, use a laser rangefinder to get an exact distance. Set your parallax knob to that yardage, then use the head-movement method to fine-tune. The markings on the knob are often just estimates.
* Hunting: In a hunting situation, you may not have time for a perfect adjustment. If you have a side knob, quickly estimate the distance to the animal and turn the knob to the closest setting. This will minimize error. Practice this estimation during your pre-season scouting.
* Benchrest Shooting: Here, precision is everything. Adjust your parallax for every distance change, no matter how small. Many benchrest shooters consider the side focus knob their most frequently used adjustment during a match.
Common Mistakes to Avoid
Avoid these pitfalls to ensure your adjustments are effective.
* Confusing Parallax with Windage/Elevation: The parallax knob does not change your point of impact. It only removes optical error. Always confirm zero after adjusting parallax, but it shouldn’t shift your impacts if done correctly.
* Not Using a Stable Rest: Trying to adjust while holding the rifle freehand is nearly impossible. The natural wobble will mask the parallax error.
* Ignoring the Diopter: If your reticle is blurry to start with, you’ll struggle. First, set the eyepiece diopter by pointing the scope at a blank wall or the sky and adjusting until the reticle is sharp. Do this once and then leave it alone.
* Forgetting to Check at Different Ranges: Parallax must be readjusted for each major distance change. Don’t set it at 100 yards and forget it if you plan to shoot at 500.
FAQ Section
What is parallax in a rifle scope?
Parallax is an optical effect where the reticle seems to move over the target when you move your eye behind the scope. This can cause aiming errors. Adjusting for it removes this illusion.
Do all scopes have parallax adjustment?
No. Many traditional hunting scopes have a fixed parallax setting, usually at 100 or 150 yards. They are simpler but less flexible for precise shooting at varied distances. Target and long-range scopes almost always include an adjustment feature.
How do you set parallax on a scope?
You set it by turning the side knob or front ring while watching a steady target and moving your head. When the reticle stops moving on the target, the parallax is set correctly for that distance. It’s a straightforward process with a little practice.
What’s the difference between side focus and adjustable objective?
They perform the same function. A side focus knob is mounted on the side of the tube for easy access. An adjustable objective is a ring on the front lens. Side focus is generally considered more convenient, especially when shooting from a prone position.
Can improper parallax affect accuracy?
Absolutely. If parallax error is present and your eye position isn’t perfect, you will not be aiming at the exact point you intend. This leads to missed shots, particularly at longer ranges where small errors are magnified. It’s a key step for consistent groups.
Mastering parallax adjustment will make you a more confident and capable shooter. It takes the guesswork out of your sight picture and ensures that any miss is due to wind, ballistics, or trigger press—not an optical illusion in your scope. Take your time to practice the head-movement technique on the bench, and soon adjusting for different distances will become a quick and natural part of your shooting routine.