# MORE THAN A MEASUREMENT: In theory, rangefinding is simply the process of determining distance. But in the deer woods, it also involves knowing what to do with that information once you obtain it.

The first hunting rangefinder I ever laid eyes on, back in 1985, was a device that once had lived a very different life.

From the world of military surplus, my friend Russell Thornberry had rescued a clunky contraption originally used to pinpoint targets for artillerymen. Russell had concluded that if you could use it to deliver a payload in combat, you could use it to aid in long-range rifle sniping of whitetails in eastern Alberta. The fact my friend showed me this battlefield gear as we hunted the valley of the Battle River was totally coincidental.

That old rangefinder worked, though not without its logistical challenges. Consisting of a horizontal tube weighing several pounds and stretching more than a yard in length, it was unwieldy at best. Russell had it mounted on a tripod, which was the only practical way to hold it steady enough to get a solid reading on the object being ranged.

Such parallax (also known as coincidence) rangefinders employed the same "stereo" principle our own eyes us to gauge the distance to an object. There were mirrors in each end of the tube and a central eyepiece, offering slightly different points of view of the object in question. Measuring those variances by way of light angle, the rangefinder calculated how far away the object was. The wider you could position the mirrors, the farther and more precisely you could determine range of whatever was centered in the viewfinder.

If this sounds familiar to you old-school bowhunters, that's because it was the principle behind rangefinders from New York's Ranging Co. In the 1980s and into the '90s, they were the archer's go-to tool for determining distance. You spun a wheel until the target came into focus, then read the range off a dial. The results weren't perfect, but accuracy was sufficient in decent light and at standard bow shot ranges of the day.

I saw Russell's parallax range-finder in action soon after the birth of North American Whitetail and a few years before the laser rangefinder became a go-to item for hunters. Once lasers arrived, parallax models began falling out of favor.

The laser itself dates back to 1960, and it quickly found its way into military applications. Eventually, it reached the public. In '92, Leica launched the Geovid, the world's first line of laser-equipped binoculars. Seven years later, Nikon debuted its Laser800, the first handheld laser rangefinder for hunters. Seven years after that, Burris brought out its revolutionary LaserScope. At that point, laser rangefinding was fully upon us.

The inner workings of such rangefinders are complex, but they operate on a simple principle. Because light travels at a nearly constant speed (depending a bit on what might be impeding its progress), distance is calculated by how long it takes the laser beam to reach the target and bounce back to its origination point.

While there are variations on this method, today's laser rangefinders all operate in the same basic way. But that doesn't mean they're all equal. Extra features have made some useful than others, provided you know what those features are for and how to use them.

ACCURACY & RANGE VARIABLES

Laser rangefinders are amazing, and they're easy to use. Of course, the more you know about what affects their performance in the field, the more good you can get out of them. For hunting with bow or gun, a rangefinder is useful only if it works quickly and accurately under real-world conditions.

Most ranging "failures" aren't the device's fault. Environmental factors can hamper our ability to achieve accurate results. Atmospheric conditions, target choice and the ever-present human element all can impact rangefinder effectiveness.

Even on a bluebird day in the wilderness, the air through which a laser beam travels isn't pure. All sorts of stuff--dust, pollen, smoke, fog, snow, rain, a butterfly, you name it--can impede the beam's journey to/from your target. If that impediment is serious enough, it can affect performance.

Some rangefinders have a fog/rain/snow mode. Depending on brand and model, you might also be able to switch to "first" (close) or "distant" (far) mode, telling the device which part of that field of view matters more to you. The names of the modes vary, but the idea is the same: to range what's either in front of an obstruction or behind it, and to confirm that's what you're getting your reading from.

Just as foreign particles in the air can affect laser performance, so can the target the beam hits before returning to sender. Take a reading off a bright-metal barn roof and you'll likely get a perfect measurement. Do the same with a black cow standing in the shade of that barn and you might not. Reflectivity matters. A shiny metal surface simply provides better "bounce" than a dark cow does. So some manufacturers let you switch between reflective and non-reflective target modes.

We've come a long way from the days when the top rangefinders measured out to "only" a half-mile or so. Now some will range to 4000 yards. There's rumor they'll reach even farther under ideal conditions, but such claims haven't yet made it into any hunting rangefinder's marketing materials.

Of course, you could argue that's moot. Does a whitetail hunter need to know a deer (or anything else) is exactly 3,929 yards away? No. But it could be handy to verify that's how far a certain boundary fence is from where you're sitting.

FEATURES & PROGRAMS

Part of what can make it hard to get a good range reading is being unable to hold the center of the viewfinder still. If it slides off the object you're trying to range as you're pushing the button for a reading, the result can be way off.

With that in mind, this year Nikon released the 3000 Stabilized. I tried it out at the 2018 SHOT Show, and in comparison to trying to hold a standard rangefinder steady, I found it to be a huge improvement.

This technology could be a real plus in the field, especially for a bowhunter. In thick cover, many whitetails are within bow range before they're even spotted. Being able to range a deer with one hand while reaching for your bow with the other could help. I expect we'll see more brands offer image stabilization, as has happened with cameras and binoculars.

Golfers like laser rangefinders with built-in compensation for slope, because whether it's uphill or downhill, that changes the effective distance of the shot. Wind and even barometric pressure also can have major effects, as they influence air resistance. So it is with arrows, bullets and slugs. All are subject to the same physical forces a Titleist is. The difference is that when shooting a deer, you can't benefit from the bounce or roll if the shot comes up short, and you can't spin an overly long strike back toward the target. You must get it pretty much exactly right.

If you've read up on hunting rangefinders, you know there's no shortage of special features. Inclinometers measure and compensate for slope, as they do in golf rangefinders. The Burris Eliminator III riflescope factors in the effect of elevation/barometric pressure on proper aiming point. There's even wind-detecting/calculating/compensating technology in a few scopes. For now you basically must be an Israeli sniper to get one, but they exist. One day they might in the deer woods.

Even minus electronic wind doping, some of today's rangefinders offer plenty of cool features. Thanks to built-in software programs (and, with some rangefinders, programs you drop in yourself, via a micro SD card), it's now possible to use your rangefinder as a ballistics calculator.

And now rangefinding has entered the Bluetooth era, with the Ballistic Data Xchange (BDX) system from Sig Sauer. It uses the free Sig BDX app to pair up any Sig BDX rangefinder and BDX riflescope to instantly feed ballistic data right to the scope's reticle, illuminating the correct holdover. Simply range the target, put the holdover dot where you want to hit and shoot.'

JUDGMENT STILL MATTERS

In 2015, archer Matt Stutzman hit the "8" ring on a FITA target from 310 yards away. In early 2018, rifleman Bill Poor fired a .408 Cheyenne Tactical round that struck what was roughly a deer-sized target three miles from where he sat.

Due to the publicity surrounding such achievements, as well as Internet videos, social media posts and some hunting shows on TV, trying to hit targets at extreme ranges is moving from the "stunt" category into everyday life. Laser rangefinders have played a key role in this trend, addressing one huge variable in the accuracy equation.

But in hunting, just knowing the range isn't enough. It's only the starting point in making a humane, killing shot. And that's true in bow season and gun season alike. Whether a big buck is offering a verified 52-yard opportunity in bow season or a 520-yard one when you have a rifle in hand, how far he is from you is just one of the variables to ponder before shooting..

The wind is gusting from your right: a few seconds ago at 13 mph, but now at 19. Your shooting hand is frozen. Oh, and you're shaken by the size of the buck. The doe he's tending is ready to bolt--and who knows how long he'll stand there once she breaks? You know you have but a few seconds to get on the buck and kill him. One shot is all you can hope to get.

The most critical factor in using a rangefinder is the same one we face even when not using one: the need for self-regulation. Technology might seem to have removed or at least greatly reduced that need, but it remains front and center in the quest to kill cleanly.

"Modern crossbows have extended a crossbow hunter's effective range, compared to designs from 20 years ago," notes Rick Bednar, president of TenPoint Archery. "However, this should not be a motivator to take shots beyond ethical archery-hunting distances. In all cases, our company recommends shooting your crossbow--regardless of brand--at ethical distances of 60 yards or less while hunting.

"Even modern crossbows, shooting arrow speeds over 400 feet per second, have trajectories that arc over 90 inches--7 1/2 feet--from 20-100 yards," Rick explains. "A small breeze or an animal's normal movements can easily create a poor shot or an entire miss at the far end of that range."

That principle doesn't apply just to crossbows, or even archery in general--it also extends to firearms. Depending on a host of variables, at some point even a precisely ranged deer is just too far away to try to kill.

IN CONCLUSION

There are many great rangefinders and highly accurate bows and guns. But having a setup capable of dropping its payload on the money at long range is just part of filling a deer tag. The question isn't necessarily how much to hold over or how much wind drift to allow for. Often it's simply: Should I even shoot?

We can set all sorts of hunting regulations, but one thing we can't control is a shooter's judgment. The job of shot selection falls to the hunter alone. A rangefinder reduces the risk of a miss or bad hit, but its readout must be combined with a review of the conditions and an honest self-appraisal of skills before it can translate into a clean kill. And in the deer woods, that's the only outcome to shoot for.

BY GORDON WHITTINGTON