Know Your Rangefinder Inside and Out

Years ago, I went on a combo deer and antelope hunt in Montana. It was a semi-guided hunt, and on the first day, I was asked if I wanted to hunt whitetails from a treestand or muleys via spot and stalk.

Being a Western guy, I jumped at the muley option. My guide dropped me off along the road with some basic instructions: Start hiking, and start looking. Within an hour, I spotted a band of bucks moving across some lower grass-choked foothills. There was very little cover around, so I knew my best chance would be jogging uphill and then looping around to get in front of the deer.

My plan worked. I got in behind a clump of brush, and when the biggest buck walked past at what looked like solid shooting range, I brought my rangefinder to my eye and pressed the button. With the arrow on the string and my bow ready to go, I was eager to see the distance flashing inside the lens. However, all I saw were four hash lines, blinking, as I kept scanning for the shooting range. I kept pushing the button, and the 170-class buck kept walking. Nothing. I couldn’t believe it. Right before the buck headed over a rise, the unit flashed “53” yards, but it was too late.

Understanding Rangefinder Technology

That experience left me perplexed and totally frustrated. Weeks before the hunt, I acquired a new rangefinder — one that I had not tested thoroughly. On my backyard targets, the unit registered quickly and accurately, so I didn’t anticipate any problems. But in this real bowhunting situation, it performed horribly, nowhere near like my old tried-and-true unit. This prompted me to delve further into how a rangefinder is made.

What I discovered, was that laser rangefinders are relatively simple tools. They emit a laser beam, or a burst of beams, at the intended target. This beam(s) is reflected off the target and sent back to the receiving lens of the optic. A sophisticated internal clock measures the time in which the beam is reflecting back, and the distance is calculated. However, there are certain attributes that make each style of rangefinder perform better than others.

For starters, not every rangefinder incorporates the same optics. Like binoculars, a well-built rangefinder with exceptional optics will yield better performance, such as a clearer view to the target and better instrumentation to precisely calculate the distance, usually to the half-yard. Secondly, the intensity in which the laser beam projects out of the unit makes a big difference as well. It must be strong enough and narrow enough to bisect the target, and not the various types of obstructions surrounding it. It was clear in this opening bowhunting scenario that the rangefinder I was using was emitting a flood-like laser beam, and it could not acquire a solid reflection off the deer’s side with grass and twigs in the way.

There are also different modes on today’s rangefinders you can select, depending on the ranging situation. In thick cover, you can choose “brush” mode, or something similar. Some units label it as “distant priority,” which measures highly reflective objects behind smaller obstructions. The opposite of these modes would be “field” or “first target priority.” In my experience, not all of these modes work similarly. I have a 15-year-old rangefinder that seems to never fail, regardless of the situation. It does not have a mode, but it casts a precise beam, and in less than a second, I have the distance. The instrumentation on this archaic unit is phenomenal, despite its lack of “high-tech” features.

The moral of all this: Test any new rangefinder religiously before hunting with it and compare it to other models. Experiment between different modes in a myriad of situations, and determine what works best for acquiring fast, accurate readings — well before hunting season.

Check For Consistency

I have a huge box of laser rangefinders I’ve used over the years, and each one gives a slightly different reading at 40, 50, or 60 yards. Sometimes this discrepancy is a half-yard, and sometimes it’s two or three yards. The actual distance it registers isn’t super important, as long as it’s consistent from one attempt to the next, especially under various weather conditions. Lasers function better in overcast conditions compared to bright, sunny days. For this reason, I like to keep a log of my distance readings on my home range. I do this for several weeks to ensure my new rangefinder is registering targets reliably. A couple yards off at extended distances (beyond 50 yards) could cause you to hit the target low or high by several inches, and that’s with a perfect shot.

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To get an idea of how much arrow trajectory plays into all this, use this simple online calculator by entering your bow’s arrow speed and setup details: mimkr.bplaced.net/bc/. You’ll be astonished by how small the margin for error actually is, the farther out you shoot.

One other note, because your rangefinder’s distance readings may be different from the actual true, measured distance, or the yardage stakes at the shooting range, be sure you sight in using your specific rangefinder’s readouts. The same goes for a friend’s rangefinder. Don’t go by his; go by yours.

Speed Is Imperative

I’m predominately a spot-and-stalk or walk-and-ambush-style bowhunter. This form of bowhunting brings me the most enjoyment, even though I’m not always successful. Regardless, when I do spot game, I’m usually required to think, move, and shoot quickly. I need my rangefinder to work super-fast, otherwise I could miss a valuable shot opportunity. For this reason, I will no longer use a rangefinder that doesn’t function with ease. You should also be able to toggle between different modes in less than a second or two. If the rangefinder doesn’t allow for this, then consider it a liability.

I like to carry my rangefinder in a loose pouch. Once I know a shot is imminent, I usually remove the rangefinder from the pouch and tether it around my neck. This system is absolutely stealthy and super-fast. You should be able to deploy your rangefinder in less than two or three seconds and have the distance in another one to two seconds.

Angle-Compensation & Bow Performance

Bowhunting the mountains means extreme up and downhill shooting. This is where a rangefinder’s angle-compensation feature can save the day. However, this feature must be tested to ensure it jives with your bow’s arrow speed. Some models come with bow or rifle modes, which improves the accuracy of horizontal-distance reading, since it is calibrated for average arrow speeds and not bullet velocities.

Because exact readings at longer distances are imperative, attempt to verify the accuracy of the angle-compensated readings against your sight’s settings. There will likely be some variances. My favorite place to hunt is in the steep alpine mountains of Nevada and Colorado. In this environment, 25 to 30-degree slopes are very common. I like to find a steep hillside and place a target butt between 50 and 60 yards. Then I begin testing my rangefinder readings against my arrow’s trajectory. I shoot three-arrow groups several times to establish impact patterns. This testing gives me some idea how much I need to subtract or add to consistently make uphill and downhill shots. Once I have the data, I make a small +/- chart in Excel, which I tape to my rangefinder. With only a quick glance, I can cut or add the distance I need to make the shot.

Surely, there’s a lot of extra work involved with becoming rangefinder ready, but in the end, it’ll keep you dialed-in and shooting with confidence.