September 23, 2010
By Wayne van Zwoll
The author takes up the cause of leaving your scope set close to the center of its range.
By Wayne van Zwoll
At the distances at which most game is killed, powers around 4x are in many ways superior to the really low or really high magnifications.
Power begets a lust for more. Mental, physical, political, ballistic--or optical--more power seems better than less. But it isn't always. Powerful riflescopes can make you miss.
Well, not exactly. When you miss, it's hardly ever the fault of your scope. Still, you can improve your shooting afield by keeping that power dial in the middle of its range (or at the bottom, depending on the scope). Magnification of 3X to 6X is hard to beat for big game hunting, whether you're in the woods or on the prairie. At 3X, an animal 150 yards away looks as big as one would appear 50 steps distant with your naked eye. At 6X, a deer 300 yards off looks as it might to the naked eye at 50.
I don't need a bigger target image than the chest of a deer at 50 yards, and you probably don't either. In fact, I've killed several animals with iron sights at over 100. By that measure I should have no trouble with a 4X scope at 400 steps, because the reticle affords a much more precise aiming point than do iron sights, and a clearer, less obstructed view of the target--while delivering the same apparent image size.
The longest shots I've taken at deer and pronghorns (460 and 420 yards, respectively) were accomplished with 4X scopes, the longest at elk (300) with a 3X. I could have used a 6X scope to advantage in all three cases, but it wasn't needed in any. If you can see the bullet's designated landing zone around the intersection of your crosswire, you have magnification enough.
By that dictum, most of us would need modest scope magnification most of the time. Few animals are so difficult to approach that they must be killed beyond the point-blank range of modern rifles--say, 250 yards--where a 3X or 4X allows for quick but sufficiently precise aim.
I've seen many animals missed and crippled at extreme range, others taken with long shots when they could have been stalked and killed more neatly up close. It seems hunters think they need more magnification than they do, and when they get it they shoot far because the animals look easier to hit than is the case.
On the other hand, low power--below 2.5X--has little to recommend it. Anyone at all familiar with scopes can aim as quickly with 2.5X or 3X (or even 4X) scope as with iron sights. As your eyes lose acuity with age, scopes get faster relative to iron sights. And you don't need a big objective bell to snatch quick aim or get a bright image with scopes of modest power.
A straight objective on a one-inch scope gives you about 22mm of clear lens diameter--enough to provide 7mm of exit pupil at 3X. A 32mm objective at 4X gives you 8mm, a 36mm delivers 9mm. As 6mm of exit pupil is all your eye can use in the dimmest of hunting light, reducing magnification below 3X does nothing for brightness. The only benefits are wider field of view and more latitude in eye placement behind the lens. Neither is compelling.
A 2.5X or 3X scope gives you 40 to 50 feet of field at 100 yards--at least eight deer lengths. A 6X shows you enough space for a barn dance. As for finding that image, a rifle properly stocked should put your eye naturally on the scope's axis. You shouldn't need field beyond the boundary imposed by the ocular housing.
The disadvantages of super-low magnification give me pause. Field curvature increases, and the muzzle or front sight appears in the field--creating a distraction. For the utmost in speed on dangerous game rifles and tactical carbines, you'll want irons, perhaps a red dot sight. But where shots come at over 150 yards, the middle powers offer far more precision, with a sight picture as quick to read as a traffic light.
Most midrange variable scopes give you more versatility than you can use. A common mistake is to crank variables too high. Legion are the tales of animals lost because the rifleman couldn't take fast aim up close. A 3-9X variable should stay at 3X until you need more power. Almost always you'll have time to dial up more magnification for a long poke; short shots are typically urgent.
I once neglected to remind an elk hunter to keep his 2.5-8X variable at the low setting. When a record-book elk popped out of a ravine 60 steps away, he couldn't find it in the 8X glass. He would never have needed 8X magnification for an elk.
The main reason riflemen find middle powers inadequate at the range is that they use target faces with tiny aiming points. I prefer white paper squares sized for the distance, reticle and magnification. My standard 50-yard target for iron sights is a full sheet of typing paper. The reticle in a 4X scope looks good against a six-inch square at 100 yards.
I typically use four-inch squares for 6X scopes and eight-
inch for 2.5X and 3X magnification. It's easy to quarter that simple clean-edged square. You can shoot surprisingly tight groups with big bullseyes. I once printed a three-shot cluster that miked .14 inch--using a .375 with a 3X scope.
Remember that you don't have to see a bullet hole to hit it. All you have to know is that you broke the shot in the middle of your target. Do that repeatedly and an accurate rifle will give you tiny groups in the center of a bullseye as big as an elk's chest.
High magnification comes at a price: small field, shallow depth of field, reduced brightness and more apparent movement in the sight picture. You'll want to see the movement you can control but not all the jumps and jitters you can't. Trying to rein in all that "noise" will slow your shot. A relatively steady reticle encourages you to shoot before you run out of breath or your muscles tire and the sight picture deteriorates.
I've long favored fixed-power scopes, for several reasons. They're lighter and more compact than variables, less complicated and less costly. They're optically superior (less glass and no erector movement) and can be mounted farther forward on the rifle. Another reason is that, in 40 years of hunting, I've never shot an animal that couldn't have been taken with a 4X scope. Its popularity, and that of the 2.5X, during the formative stages of the scope industry is not surprising. Hunters killed game with both.
Higher power surely has its place. You'll want to dial up that 2.5-8X, 3-9X or 3.5-10X for long pokes at coyotes, and if you're scoping a prairie dog gun, you're best served by magnification in the upper teens. I shoot smallbore prone matches with a 20X scope.
Most big game animals, however, die between 50 and 200 yards
from the rifle--where scopes of 3X to 6X shine. Higher scope power may enable you to see detail at longer ranges, but they can't help you dope the wind, hold the rifle still or break the shot cleanly. You'll shoot more confidently and, I predict, more accurately, closing a few more yards and quartering the vitals with a scope of middle power.