Advanced Terms and Riflescope Types Explained

In Part 3 of ‘choosing the best riflescope’ the magnification aspect of a rifle scope is explained. The difference between variable and fixed power scopes and the pros and cons are discussed as well as the best practical hunting scenarios to use them in.

Types of Magnification

Variable Magnification Scopes

The Power Ring is used to select the magnification level on a variable magnification scope. As mentioned before, always mount your scope on its highest and most demanding zoom setting. If you can comfortably see through the sight for the highest magnification then it will be easy to sight when using the lower magnification settings.

Fixed Magnification Scopes

On this type of riflescope the power ring is absent since the focus is fixed at one setting and so it is vital that you consider what you are going to use the scope for before buying. Many hunters prefer fixed power scopes as they are simpler to use only requiring elevation and windage adjustment. They also have less moving parts to malfunction.

Handgun Scopes

If using a scope in conjunction with a handgun or pistol the easiest magnification for a beginner is the 2x scope. As already mentioned in this article when you increase the magnification then it’s harder to sight a target and get a clear picture and the eye relief is much more critical. A high powered variable scope on a handgun is usually only used from a resting position whether on wood or the top of a wall.

Best Magnifications to use for Common Hunting Applications

Whitetail Deer Hunting

For whitetail deer hunting a variable zoom scope of 3-9 magnification range is fairly standard but you could use up to 4-12 or 4.5-14. You can leave your magnification on the highest setting when sighting across plains and open country where you expect to have a longer distance between you and your target.  A fixed power scope of 4 is also a great choice for Whitetail Deer as the scope is easier to sight because it only needs to be adjusted for windage and elevation.

Prairie Dog Hunting

For prairie dog hunting and longer range shooting the higher magnifications of 6-20 or even 8-25 come in handy. You will find that on hot days ripples caused by heat rising and the visual distortions caused by mirage effects can really make sighting difficult and have a significant effect on accuracy when you are using high-powered scopes.

Hunting Deer or Turkey at Short Range

For shorter range applications, such as hunting deer or turkey with a shotgun and slugs, there is no need for high magnification. A fixed power 2 scope should be used, but you can get away with using a 3-9x variable or even a 2-7x. For shotgun scopes there is maximum eye relief so as to prevent the ‘scope eye’ injury from happening. For the lower power scopes, parallax is usually set by the factory at 50, 75 and even 100 yards.

Long Range Target Shooting

Fixed power scopes of up to 24, 36 or even 40 power are used in long range target shooting. Adjustments and Turrets The Adjustments and Turrets on your scope are for adjusting the elevation and windage. Elevation turrets are found on the side of the scope and the windage turret is located on the top of the scope. If you have an adjustable zoom scope then you may also have a parallax adjustment turret on the opposite side of the scope to the elevation turret. Both the windage and elevation turrets are calibrated in minutes of angle, MOA.

Minutes of Angle (MOA) Adjustments Explained

A minute of angle is a unit of measurement of a circle, at 100 yards this unit is 1.0472 and is called 1 inch. It is directly proportional to distance, eg. At 200 yards MOA is 2 inches. When a scope says it can be adjusted by ¼ MOA it means each ‘click’ or the smallest possible adjustment will change your point of impact by ¼ inch at 100 yards. The easiest to use turret adjustments are the ones that click. Giving an audible indication makes it much easier to know how much you are changing your point of impact by. There are friction type turret adjustments which are theoretically infinitely adjustable but it is harder to keep track of exactly how far you’ve adjusted it, unlike just counting clicks.

Elevation Adjustments

The elevation adjustment controls the up and down position of point of impact of your shot. You want to line up where your rifle actually shoots when you point it with where your cross hairs are telling you the point of impact should be. Your point of impact will also change depending on the ammunition you are using. If the ammunition is heavier then generally it will fall quicker over distance meaning that you will have to compensate the elevation accordingly.  The elevation on newer riflescopes is adjusted in MOA.

Windage Adjustments

The turret on top of the scope is for windage adjustments to cancel out the effect of wind on the trajectory of the bullet. Adjusting windage will change the point of horizontal impact to either the left or right. In theory, you need to have practice shots to determine the amount of horizontal adjustment needed for each speed at which the wind blows. However as wind also impacts how far a bullet will travel due to applying either down force or uplift, it is not a straight forward calculation and requires time and patience to match the adjustment to the conditions on the day of the hunt. Windage adjustments are also made in MOA.

Parallax and Parallax Adjustment

Parallax is an unwanted effect when using riflescopes and is best described as how the crosshairs move across your target when you move your head from side to side. It means that your shooting will be less accurate even if you are shooting correctly. If you could keep your sight directly through the centre of your scope every single time you made a shot then it wouldn’t be a problem but as we aren’t perfect all the time it remains a problem affecting scope accuracy. Most of the low powered scopes today are set to be parallax free up to 100 yards. Anything above 10x usually has an option to adjust the parallax using a parallax adjustment turret on the side of the scope. You can usually set this for different distances and these are usually labeled on the turret as possible options.   You can test your scope for parallax error by moving your head from side to side while looking down the sight. If the crosshairs move across the target then you have a parallax error and need to adjust the scope.

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