Parallax adjustment with a side focus

VIDEO

Traditionally, rifle scopes had a fixed parallax set at 100 meters or 100 yards; however, with the advance of shooting sports, such an approach was not adequate anymore. Scopes with fixed parallax offered the best resolution only at one distance (100 meters/yards) at which the target was in focus. At all other distances, the picture was less sharp or even blurry. An even bigger problem with this type of scope was the fact that, when shooting at the target, not at the same distance as the scope parallax setting, the shooter had to be very careful about his eye alignment with the optical axis. If the eye is moved away from the optical axis, the reticle on the target will move, which will worsen the accuracy. Since these errors are small, the fixed parallax option is still considered accurate enough for traditional hunting. For sport shooting, though, such small error leads to poor results. Parallax errors become more pronounced with magnifications higher than 12x, and that means the majority of scopes with magnification range under this value need no parallax adjustment.

With the ability of parallax adjustment, the accuracy of the riflescope is greatly enhanced at all distances. The shooter, however, has to adjust the parallax setting before making the first shot. Such scopes usually have AO – Adjustable Objective or SF – Side focus acronym in their name.

With SF – Side focus scopes, parallax is adjusted with a rotation of the turret on left side of the main tube. Such an approach offers easy adjustment of the parallax in the prone position and is the best solution for situations when parallax must be adjusted often. Due to this reason, such scopes are usually used on tactical scopes and similar, where parallax is adjusted before each shot and distances to the targets change rapidly. Scopes, which offer parallax adjustment with a side focus, are usually bigger and heavier than counterparts with parallax adjustment on Adjustable Objective. They are also more expensive to produce. Due to the size of the internal mechanism for side focus adjustment, the majority of such scopes have a tube diameter of 30mm or more.

The easiest way to correctly set the parallax is to look at the target and gently rotate the ring on the side focus. When the target is in focus and the image offers the best sharpness, move the eye from the optical axis to any direction. If the rifle is properly supported and fixed, the reticle should not move on the target when the eye is moved from the optical axis. If it does, parallax adjustment must be fine-tuned until the reticle is still, even if the eye of the shooter is moving around the optical axis.

Do not mind the meters or yards written on the adjustable objective, since they only provide an approximate value. There is nothing unusual if these values do not correspond well with the actual target distances.

Video presentation of Parallax adjustment on the objective bell

Filters

Sort

Athlon Argos HMR 4-20x50 SFP

As low as $389.00 Regular Price $429.00

View Product

Add to compare

Athlon Argos HMR 2-12x42

As low as $359.00 Regular Price $399.00

View Product

Add to compare

Filters

Sort

VIDEO

General features of rimfire riflescopes

Rimfire riflescopes are designed for scopes chambered in .22 LR and similar calibers. In this scope category, you can find anything from basic scope for "plinking" to serious scope for 50m Benchrest competitions.

Reticle

There are a couple of features that most rimfire scopes share. The first one is a thin reticle in the second focal plane. The second focal plane reticle is important to have as it does not change in size with the increase (or decrease) in magnification power. The reticle thus remains thin at high magnification, providing a minimal obstruction of the target.

Rimfire rifles are compact and small, so it is quite important that rimfire riflescopes feature these same two qualities.

Magnification and Parallax on Rimfire rifle scope

A high magnification combined with an adjustable parallax is incredibly useful to have on such a rifle scope. With high magnification power, the user can aim much more precisely.

The adjustable parallax allows for a precise focus setting. Certain rimfire scopes with lower magnification power come with a fixed parallax.

1-inch and 30mm tubes are used, the former being more common in the field of rimfire riflescopes.

Vortex Crossfire II 4-12x40 AO Rimfire Rifle scope Reticle Black Matte

Vortex Crossfire II 4-12x40 AO (SFP reticle) Rimfire Rifle scope Black Matte

Why do rimfire scopes need an adjustable parallax?

Shooting with a rimfire riflescope is typically done at a close range up to 70 m. In most competitions of this type, great accuracy is needed. For this reason, rimfire rifles are designed to be accurate, and only an accurate rifle scope can do them justice.

To achieve the desired accuracy, the target must be properly focused on high magnification power, which is achieved with adjustable parallax.

There are two types of adjustable parallax:

adjustable objective ring
side focus turret

Scopes with an adjustable objective ring are generally less expensive since fewer parts are needed to manufacture this system. It is also lighter. The downside of such a rimfire scope is the difficulty to reach the ring while in the shooting position.

Side focus rimfire scope is heavier and more expensive, but the parallax knob can be easily accessed while in the shooting position.

Is an illuminated reticle needed in a scope?

Most of these rimfire scopes are used for target shooting during the day – an illuminated reticle is not needed.

Delta Optical 6-24x42 AO Rimfire Rifle Scope Reticle Black Matte

Delta Optical 6-24x42 AO Rimfire Rifle scope Black Matte

Best rifle scopes

Below, the most popular rimfire scopes are listed.

Parallax adjustment with a side focus

VIDEO