Big, Bright, Sharp,
Flat and Clean

The bull could have popped up across the canyon, early. But glassing had yielded only a raghorn elk looking in vain for love. We’d plunged into the timber, down a north slope. The sun had broiled away the shadows when we started back up a draw, grappling for handholds of buffalo berry and nettles.

He blasted from an aspen windfall at perhaps 30 feet. “Shoot!” I screeched. The fellow was quick with his 7mm. Scrubby Doug-fir limbs swallowed whale-tail rear tines.

“He filled the scope,” gasped my hunter, still heaving from the climb. I’d heard it before, from men who’d managed to miss anyway. But at least one of these two bullets had struck and I told him so.

We scrambled up into rocks still oozing dust and found the bull dead.

My client in that steep Utah gut proved a scope can deliver very fast aim. Faster, even, than iron sights. No need to align a reticle — just paste it where you want the bullet to go. Because it appears in the same plane as the target, your eyes don’t waste time focusing.
Still, the myth scopes slow you down has survived generations who should have dismissed it. And I’ve seen animals escape hunters who failed to catch aim with their scopes soon enough. How come?

A scope should deliver a big, bright, sharp image as soon as you cheek the rifle. It’s painfully true any hunter whose sight picture doesn’t measure up is largely responsible for it.

Big

Field size is almost exclusively a function of magnification. Want a field generous enough for fast hits in thickets? Carry variable scopes set no higher than 4x. You’ll have time to bump it up if a long shot or a small target calls for more power. Just twice in 50 years have I needed more than 6x.

Modest power also affords you less critical eye relief. Take advantage of it by installing the scope well forward, so you must slide your cheek ahead when mounting the rifle offhand. You’ll get a full field of view quickly and enough eye relief when sitting and prone to protect your brow.

Bright

All but the least expensive scopes these days feature fully multi-coated lenses. It means every lens surface, inside and out, has been treated with rare earths to enhance light transmission across a range of wavelengths. An uncoated glass surface can lose 4% of light to reflection and refraction. Multiply this by all air-glass interfaces in a scope and you understand the dim images hunters endured before Zeiss used magnesium fluoride to hike light transmission in the 1930s. Insist on fully multi-coated optics!

Brightness also depends on exit pupil, the diameter of the pencil of light reaching your eye. EP is a function of magnification and front (objective) lens diameter in millimeters: EP=D/M. The lower the magnification and the bigger the lens, the brighter the image. Your healthy eye dilates to about 7mm on a dark night; figure 6mm in the dimmest shooting light. Old eyes lose their flexibility, further reducing the dilation limit. An EP bigger than your pupil’s diameter won’t boost brightness. A 3-9×36 scope set at 4x delivers an EP of 9mm. At 6x, the EP is 6mm — and the image appears just as bright. At 9x, the 4mm EP limits brightness at dawn and dusk, when your eye dilates to a diameter bigger than 4mm.

I’ve never seen a hunter miss a chance because his scope’s power dial was set too low. Legions have muffed opportunities because the dial was cranked up, throttling both light and field of view and in some cases making eye relief so critical the hunter lost time seeing anything through the scope.

Sharp

Sharp sight pictures also begin inside the scope, with top-quality glass, then careful lens finishing. Lens grinding and polishing account for most of the time invested in building a scope. But what you see through those lenses also depends on how you focus them.

Increasingly, hunting scopes wear focus/parallax adjustments. Early on, these were sleeves on the objective bell you indexed to the shot distance to bring the target into sharp relief and nix parallax — the apparent shift of the target behind the reticle if you moved your eye off the scope’s optical axis. Now such adjustment is usually provided in a more convenient dial on the left-hand side of the turret. Hunting scopes without a focus/parallax ring or dial are typically set for sharp focus at 100 or 150 yards.

You can focus a scope’s reticle with the eyepiece (ocular housing). Traditionally, this was done by loosening a lock ring and spinning the eyepiece in or out on the fine threads that secured it to the scope tube. Now scopes have “fast-focus” or “helical” eyepieces without a lock ring. Adjustment is quick and easy. Strangely, I hardly ever see a hunter adjust the eyepiece on a new scope or one on a borrowed rifle!

Clean

Hewing to a 2-1/2x lower limit, you’ll also avoid the distraction of a front sight or suppressor. You can see more of the target with a scope than with iron sights, as the reticle obscures less than does a front bead, much less than an open rear sight. Why erase the advantage by adding muzzle hardware to your field of view. Or festooning the reticle with tentacles? A cluttered sight picture retards aim.

You’re smart to use a simple reticle, bold enough to catch your eye in any light but without extraneous lines, bars, dots and tics. These have a place in long-range competition but serve no function under the conditions most game is shot. They drag your eye inside the scope, where it’s tasked with deciphering instead of aiming.

Dust, water and scratches on exterior lenses are also clutter, though they’re out of focus and often not even apparent as you aim. They also reduce brightness. Hygroscopic lens coatings to bead water are now commonly applied during scope manufacture. Scratch-resistant coatings are more recent. Both help keep your field of view clean and bright. Lens caps make sense if you hunt often in rain or snow. I pocket a Kleenex to dab dust and moisture off glass. A daily spray of lens cleaner, gently dried with a Kleenex in circular swabs, has much to recommend it.

Your hunting scope has more magnification and features than you’ll likely use killing game. But what’s always in play is what you see when you aim. A field that’s big, bright, sharp, flat and clean hikes your odds for a hit.

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