A Beginner’s Guide to Riflescopes
In 1844, a competitive rifle shooter named Morgan James wrote a book titled The Improved American Rifle, in which he...
In 1844, a competitive rifle shooter named Morgan James wrote a book titled The Improved American Rifle, in which he described a scope and mount of his design that is generally regarded as the first practical optical rifle sight. By the 1860s, scopes had progressed enough for Union Col. Hiram Berdan’s Sharpshooters to use scope-sighted rifles to pick off Confederate officers and artillery crews at comparatively long distances.
Early scopes lacked much in optical quality and durability, however, and until the 1950s were regarded with suspicion. When Roy Weatherby introduced his Mark V rifles in 1958 without iron sights, it was considered further proof that he was one crazy Kansan. What were you going to do when your scope broke?
But history proved Weatherby correct. Now we use glass sights almost to the exclusion of iron, and progress in the optics industry moves at a gallop rather than the stately trot of previous decades. Some of today’s economy scopes are as good as medium-priced models from when the 20th century finally got tired and went away. The current medium-priced scope is probably better than a then high-priced one, and what is now top of the line had not yet been dreamt of. Today’s scopes are not perfect by any means, but oh boy, are they good.
Let us have a closer look.
Bells and Tubes
Riflescopes are now drawn from aircraft-grade aluminum, which is terrifically strong and much lighter than yesterday’s steel tubes. Where steel was blued, aluminum is anodized or otherwise coated. There are shiny scopes and matte ones. The former act as a warning light that says to animals, Why die when you can run? A hunter needs a shiny scope like he needs a freshly polished tuba.
At the two ends of the scope tube are the objective-lens housing, or bell (the one up front), and the ocular-lens housing, or bell (the one that can crack you in the eyebrow). As the power of a scope increases and/or the manufacturer wants to admit more light, the diameter of the objective bell increases. On most hunting scopes, this bell is between 32mm and 50mm, and as a rule, you don’t want to go bigger than 50. The bigger the lens, the more a scope weighs and costs, and the more difficult it is to mount on the receiver. I’m perfectly happy with 40 or 42 most of the time.
Between the two lens bells is the tube, and tubes come in two diameters: 1 inch (most popular in America) and 30mm (European, but making inroads here). It’s claimed that 30mm tubes let in more light. I doubt it. What is beyond dispute is that a 30mm tube is structurally stronger, and it allows more latitude of adjustment. This means the reticle has more room to move up and down, right and left, so you can still get your rifle to put a bullet on the target and re-sight your rifle if something gets knocked out of alignment.
This is the distance between the ocular-lens bell and your eye, and it’s important because if you don’t have enough of it, you will eventually hear the melodious splat of aluminum splitting your eyebrow. For a hunting rifle, a scope should have a bare minimum of 3 inches of eye relief, and 31⁄2 is far better. On a heavy-kicking gun, 4 inches is the least you want. Or you can go to the ER on a regular basis to get stitches.
All scopes have adjustments for windage (lateral), elevation (up and down), and focus for the individual shooter’s eye. Many scopes intended for long-range shooting also have an adjustment for parallax. Let us take them one by one.
It is in the area of windage and elevation adjustments that scopes fall furthest from perfection. Both are controlled by dials, or knobs, located on the adjustment turret, which is midway down the scope tube. The elevation dial is at 12 o’clock, the windage at 3. These dials, via a system of small, fragile, and treacherous parts, shift the position of the crosshairs, which in turn moves the bullet’s point of impact. Most all scopes claim to change the point of impact by 1⁄4 inch per click at 100 yards. In reality, they (including scopes in all price ranges) do what they please. Four clicks of right windage may move your shot a half inch, or an inch and a half, or not at all—and you just have to live with it. What’s more, all these small, fragile parts can be shaken loose by recoil, or by a fall, or by baggage handlers. In the past four years I’ve seen four scopes come unglued from these causes.
The best windage and elevation adjustments move with a positive click, which helps you keep track of them even when your hand is cold, or gloved, or palsied. Because of the increased interest in tactical and long-distance shooting, an increasing number of scopes have exposed dials with no caps over them. I used to think those had no place on a big-game rifle, but if they can stand up to what the military puts them through, they can take your abuse.
Reticle focus is the simplest of all adjustments, necessary because all eyes are not the same. To focus the reticle of a scope, unlock the ocular-lens bell, point it at something blank like the sky or a wall, turn the until the reticle appears sharp, and then lock the bell in place. If there’s no locking ring, you need a better scope.
This leaves parallax. Just as you focus a binocular for a particular distance, so must you focus a scope. Most big-game models, typically used at short to mid range on sizable targets, are focused at the factory for 150 to 175 yards. A scope used for small targets and/or at long range, however, must be focused manually for a precise distance via the parallax adjustment, offered either as a calibrated objective-lens bell or as a 9 o’clock dial on the turret. If the parallax adjustment is set for the wrong distance, your target will appear to be where it isn’t. This is called parallax error and causes you to shoot at the wrong spot.
In the 1960s, Leupold developed the Duplex crosshair, and it has been the standard since. The Duplex consists of four heavy crosshairs that taper sharply to fine ones as they near the center of the image. This pulls your eye to the center and allows for fast, precise aiming.
There are fine Duplex-style reticles on varmint and tactical scopes, and heavy ones on dangerous-game scopes, and of all the reticles out there, I believe it’s the best.
In recent years, manufacturers have added LED lights to reticles. They function extremely well and, I believe, improve aiming speed. If you buy a scope with an LED light, however, make sure that the reticle is one you can use well if the light craps out. And bring an extra battery on hunts.
Range-compensating reticles are also gaining popularity and show where to hold for a given distance. For example, with the crosshairs sighted in dead-on at 100 yards, small dots, circles, or hashmarks on the vertical stadia wire below the crosshairs indicate the hold for 200, 300, 400, 500, and sometimes 600 yards. I’ve used many and they work well—provided you read the directions and pay strict attention to detail. They only work at one designated power. Some are calibrated for mils (3.6 inches at 100 yards), others in minutes of angle (1.047 inches at 100). The correct range compensation is cartridge specific. And you must always have a laser rangefinder handy. Forget any of this and you’ll miss by a mile, or a kilometer if you’re metric.
High magnification is in vogue, but most of the time you don’t need all those Xs, and a great deal of the time, more power is a handicap, increasing mirage, visible shake, heft, bulk, and price.
Today, the variable-power scope is supreme because it offers a degree of flexibility that is genuinely useful. Here’s a rough guide to the power ranges that work best:
• For dangerous game, or big game at less than 200 yards: 1X–4X.
• For most big-game hunting: 3X–9X or 2X–10X.
• For varmint hunting: 6X–24X.
One of the most recent developments in scopes is the 6X multiplier; that is, a scope that offers six times more power at its top end than at its low end, extending the traditional 2.5X–10X, for example, to 2.5X–15X. I don’t think 15X is worth the high prices such scopes command. But a 6X multiplier that goes from 1X to 6X might be well worth the money.
If you remember one thing about magnification, make it this: On the whole, less is more.
The typical riflescope contains about eight lenses, including the two obvious ones. The quality of the glass itself, the care with which it was ground to shape, and the quality of the coating applied determine in large part how good a scope is. Even if you know nothing about scopes, you can look through a $300 model and then a $1,300 one and know instantly which is which. The difference in image quality is startling and is what you pay all that money for.
At least two scope companies, Bushnell and Swarovski, have lens coatings that disperse water into droplets so tiny that they don’t affect your sight picture, enabling you to aim in a downpour or a heavy fog. This is a highly desirable feature.
There’s a lot of shuck and jive put forth by marketing folk about scope-lens quality. I will not repeat it here. Look through several scopes side by side, and you’ll see that some are obviously better than others.
Perhaps the greatest recent progress in optical sights, which has benefited average hunters the most, has been the vast improvement made in low-end scopes. And yet, I’ve always felt that there are two pieces of equipment for which you are justified in breaking the bank: scope and binocular. There is no shame in mounting an $800 scope on a $500 rifle, and I have done so more than once.
My advice is to go out and identify the very best scope you think you can afford—and then buy one that’s a little better.