Scope parallax is the term used to describe an inconsistent view that is seen when looking down the scope of a rifle.
It is what occurs when the crosshair moves across any given target whenever your eye position is shifted. This causes the reticule to not reflect the direction that the rifle is pointing in.
This tends to be an issue in scopes with higher magnification, as it is far more noticeable in weapons with this type of scope.
As the amount of parallax within any given scope varies depending on the target’s distance to the shooter. It is crucial to make sure that you are adjusting your aim when parallax occurs.
What Is The Main Cause Of Scope Parallax?
Whenever you look through a rifle’s scope, the image that magnifies indicates where the light rays have entered the optic and become focussed.
Thus, you are seeing a projected version of the image in front of you. Therefore, parallax issues will arise whenever the image is out of distance from the cross-hairs contained inside the optic.
In order to rectify parallax issues, you will need to place the desired image closer to the reticule of the scope so that there is less room for it to move.
Then, place a reticule sticker on the window and place the picture on the other side. After doing this, the reticule will always correctly isolate the target. The vast majority of optics and scopes will allow for the shooter to adjust the focal point.
Depending on the rifle, adjustment rings can be situated towards the front of the objective lens, towards the rear or as a turret in the middle. Where these adjustments are located varies depending on the quality of scope that the rifle is using.
The following is a step-by-step guide for how to adjust parallax:
- Place the rifle into a stand or ensure that it is anchored securely at a shooting table.
- Make any necessary adjustments, removing any wobbles or altered shooting positions.
- Use the adjustment ring to position as close as possible to the target you’re shooting.
- Estimate how far away you are from your target and dial your scope accordingly.
- Take your aim and slowly adjust your eye position.
- Pay close attention to the reticule’s position. If it begins to move as you position your eye, then you are still experiencing parallax issues.
- Pay attention to how the reticule moves if you slightly move your head to the left, if it also moves to the left of the image, then it is too far from the reticule, and you will need to increase your adjustment with regard to distance. If it moves to the right, then you will need to decrease.
Parallax is commonly misunderstood amongst the shooting community. The vast majority of sportsmen believe that adjusting parallax merely requires you to bring the reticle into focus on the target itself.
However, whilst that is a bi-product of an adjusted parallax, it doesn’t explain why parallax occurs nor why adjustments can correct it.
In short, parallax will occur whenever the reticle and target are on different planes in the scope itself. If it is detectable whenever you move your eye positioning or move your head around whilst peering into the scope, then this will definitely cause your scope to be entirely off-target.
Poor eye alignment with the optic will inherently lead to missed shots. Therefore, to rectify these issues, you require the target and reticle to exist on the same plane.
For the vast majority of shooters who shoot at a range of under 250 yards, scope parallax is rarely an issue.
This is because the majority of centerfire scopes are set at 150 yards, which is perfectly adequate for shots under a distance of 250 yards. Most scopes that have been made for longer-range shooting will contain parallax adjustments, whereas pistol scopes may not.
Longer-range rifles will usually contain an adjustable ring as part of the objective lens or as a turret on the side.
A further way to adjust your scope whenever parallax occurs, is to adjust it atop infinity. Then, aim the rifle at the target and set it at a specified distance.
Once you have obtained a picture through the optic lens, you can adjust it back until the rifle’s reticle becomes clear again. This is easier than placing a reticle sticker, and it is also a far quicker process. You should aim to make your aim as crisp as you can.
To clarify that it has been corrected, you can also lift your cheek from the stock whilst looking into the scope and if you still see crosshairs moving off of the target, then you should keep adjusting until it has rebalanced to become centered.
Once you have done this, your parallax will be set appropriately, and you will be able to shoot effectively. Make sure that you lock this adjustment in to avoid having to adjust it again.
To conclude, scope parallax occurs whenever the reticle and target object are not existing on the same plane. In order to adjust parallax, you should follow the guidelines above. For most shooters, scope parallax will be a non-issue.
However, if you are shooting at long-range, then your rifle has incurred scope parallax and in this instance, you should take the appropriate measures to adjust your aim accordingly. Remember to set your parallax after readjusting, in order to avoid having to re-adjust it repeatedly.