A hunter of my acquaintance sat in a tree stand overlooking a path that was often followed by deer.  All of a sudden he was aware of a deer coming along the path at a range of perhaps 30 feet.  Quickly raising his gun, which was a special slug-shooting shotgun equipped with a 3-9X scope, the hunter found that at that very short range all that could be seen was a patch of hide.  But where was that patch on the deer’s anatomy?  The problem was that the scope was set on 9X, a magnification that is not appropriate for short range shooting in woods.  A magnification of 2.5X would have been much better.  The hunter would have been better equipped with only iron sights.

            When I bought my first used .222 Remington varmint rifle, it had a 4X scope attached.  With that rifle I created havoc on groundhogs and crows.  Later I made the change to a 10X AO scope, but my success rate on pests did not improve much because most of my shooting was on terrain where targets were at 100-150 yards where the 4X scope was adequate.  It was only on longer shots that the additional magnification was an asset.  A 10X scope is not needed for shots at modest ranges with an accurate rifle. Shooting prairie dogs at a quarter of a mile or farther is a pastime that requires the use of optical sights.  To achieve the necessary accuracy for that type of shooting, a good scope is needed, preferably one of high magnification

            I once mounted a 4-16X50 AO scope with a 30mm tube on a Winchester Model 70 Featherweight in .308 Winchester caliber.  That rifle was not spectacularly accurate and was used at short to medium ranges on targets larger than rats.  The result was ludicrous.  The scope was about half as long as the rifle and weighed about a third as much.  Moreover, with that behemoth scope attached, the rifle was top heavy and its handling qualities suffered greatly.  That rifle now wears a 3-9X36 Swarovski, which is a compact scope that is also light in weight.  The result is a rifle and scope that handles well and the scope is more than adequate to bring out all the accuracy that the rifle can deliver.

            I have read dozens of reviews of hunting rifles and most of them give groups of 1.0-1.5 inches at 100 yards.  A good 4X scope has an aiming error of only a small fraction of an inch at 100 yards.  Doubling the magnification reduces the aiming error somewhat but it does not cut this aiming error in half.  If you can shoot a 1-inch group with a 4X scope, don’t expect to cut the group size in half by going to a scope of 9X.  It is interesting to take a scope of perhaps 3-9X and shoot groups at 100 yards with power settings of 3X, 6X, and 9X.  I have done this several times in testing scopes and found that there is not much difference in the group sizes.  The aiming error even with a scope set on 3 or 4 power is considerably smaller than the accuracy limit of most rifles.  Therefore, for most rifles the accuracy obtained with a 4X scope will not be greatly improved by changing to a 12X scope.

            Generally, scopes of fixed power are smaller and lighter than are scopes having variable magnification.  Being of simpler construction, they are often more rugged.  I have had two scopes fail and both were variables.  I am still content with fixed power scopes for most shooting.

            How much scope do you need?  It certainly depends on the type of shooting that you will do.  Those who market scopes usually try to sell models that have a higher magnification range, built in drop compensators, lighted reticules, dots or bars that indicate wind deflection, etc.  In the vast majority of cases a good 2-7X or 3-9X will be all that is needed.  Such scopes are often compact and light enough that the handling characteristics of the rifle are not altered drastically.  One of my favorite scopes is a 1.5-4X that is exceptionally compact, lightweight, and bright.  I have a 3.5-18X scope that has side focusing and a ballistic compensating turret.  It cost well over $1000.  It has all the features that you would expect on a scope of this type, but at this time I do not even have it on a rifle.

            A scope cannot be in sharpest focus at all distances.  Rifle scopes of lower magnification generally have a greater distance in which the target appears in sharp focus.  In fact, most scopes of over 10X have some means of focusing them sharply.  Also, scopes of lower magnification have a larger exit pupil which means that the shooters eye can see the entire field of view without being placed in exactly one specific position.  Such scopes are usually brighter and the wider field of view facilitates target acquisition.

            An interesting test of the effect of scope magnification was published a decade ago by Hugh Birnbaum (https://www.shootingtimes.com/editorial/optics_st_optics_200710/100321).  In that test, he used scope magnifications of 1.5X, 6X, and 35X and a Remington 700 Varmint Special in .223 Remington caliber.  I won’t bore you with the details of the study, but the averages of four five-shot groups were 0.958, 0.750, and 0.708 inches.  Extremely small groups are obtained in the hunter class of bench rest competition in which the maximum scope magnification is 6X.

            My single shot .45-70 wears a 2.5X scope whereas my .22 Hornet has a 2-7X scope.  My .22-250 Remington has a 3-9X scope in keeping with the uses and capabilities of rifles in these calibers.  I am not condemning the use of scopes of greater magnification, but matching the scope to the type of shooting without being overpowered is a good idea.  A 300 hp engine is not needed to haul you around on a golf cart.  A behemoth scope is not needed for shooting at most game at reasonable ranges. Fifty years ago, the hunter with a .270 Winchester with a Weaver K4 scope attached was considered to be well equipped.  He or she still is.

PHOTO CAPTIONS

My collection of old Weaver K-model scopes includes from (top to bottom) 10X, 6X, 4X, 3X, 2.5X, and 1.5X models for different types of shooting.  The lowest was intended for use on shotguns with slugs and the highest for use on long range varmint rifles.

Scopes such as the 3-9X Zeiss Conquest (left) have largely replaced scopes like the Redfield 4X (right). 

The 1.5-4.5X Nikon scope on this Ruger 96/22M is a perfect for this type of rifle and its capabilities.

A 3-9X scope is all that is needed to bring out all the performance that this Winchester Model 70 Featherweight can give. 

A .30-30 such as this Mossberg Model 464 will be used at ranges where the fixed 4X scope is all that is needed.

The absurdity of a 4-16X50 scope on a compact rifle.

The perfect match of a Savage B-Mag .17 WSM and a 3-9X AO Leupold scope.

On rifles for general use, matching the scope to the rifle is always a good idea and don’t forget that a variable does not always have to be used on the highest magnification!