t’s hard to believe. Just twenty years ago laser rangefinders were an expensive curiosity, but today they’re modestly priced and standard kit for most serious long-distance rifle shooters. The only problem is, once you start using one it seems a laser is as temperamental an instrument as ever devised by man. One day, you can range to 750 yards on a rangefinder rated to 600 yards, then the next day you can’t range to 400 yards with the same laser!
For the past decade I’ve used eleven different laser rangefinders — owned six — from three different manufacturers, and field-tested them from the Arizona desert and northland snowfields, to the forested mountains of Eastern Europe and the rarified air of the Rockies — from dawn beyond dusk — and, at last, I think I’ve collected enough tips and lessons learned so you can get the most out of your laser.

How a Laser Rangefinder Works
To understand the fundamentals of a laser ranging device, I spoke with Bushnell’s top laser engineer, Tim Carpenter, who explained that a rangefinder uses a laser diode similar to a pen pointer, except it emits pulses of non-visible wavelength light. (For those of you technically inclined, Bushnell lasers have a wavelength of 905 nanometers, in the infrared spectrum, while visible light wavelength is 400-700 nm.)
The laser diode emits light pulses of about 35-45 nanoseconds, which reflect off the target, and then the light is optically detected in the rangefinder. Next, this tiny reflected light is amplified enough to register in multiple circuits containing a high speed chronometer that measures the time it took for the light to return from the target — which, in turn, is translated into the distance to yield a range measurement. Bushnell rangefinders are calibrated to read +/- one yard of a lazed target.
Interestingly, Carpenter explained, a laser rangefinder’s maximum range is not determined by the laser’s output power. Indeed, all Bushnell lasers — whether 600-, 800-,1000- or 1600-yard versions — employ the same strength laser light emitter. No, the maximum potential range is determined by the quality of a laser’s electronic receiver, and its ability to sense light and measure tiny fractions of seconds. The difference between low-cost and high-cost lasers largely reflects lens quality and the ruggedness of its construction. What about the effect of scratched or dirty lenses? Testing at Bushnell has found this only marginally affects the laser’s range or ability to detect reflected light.
Perhaps the least understood aspect of laser ranging is properly matching the beam’s size to the object you’re ranging. Many shooters don’t get near the maximum possible range out of their laser because they imagine it’s the size of a laser pointer beam — WRONG! Bushnell laser beams, for example, are four mils high and two mils wide, which, at 1000 yards means a beam four yards high by two yards wide! First, understand that a mil is an angular measurement which equals approximately 3.6 inches at 100 yards, and steadily widens until it equals 36 inches at 1000 yards. Now, look in the accompanying data to see what the beam measures at various distances, along with common objects this size so you can visualize what’s best to range upon at each indicated distance. Note that my examples use items which, like the beam, are approximately twice as high as they are wide.
To get the highest likelihood of ranging to a given distance, laze on an object of at least the indicated size — say, a 55-gallon barrel at 250 yards. This way your entire laser beam shines upon and reflects off the object.

Factors Affecting Laser Efficiency

Here are some tips for getting readings when initially it appears you can’t, and how to stretch your range measurements to their maximum possible. As we already noted, the laser beam usually is much larger than an animal, so find a suitably sized object at the same distance, and laze to that instead.
I’ve listed the following factors in the order of how substantively they affect laser readings — the degree of ambient light present is crucial, but depending upon conditions, all these factors will vary in contribution.


AMBIENT LIGHT: Bright sunlight or strong artificial light reduces your laser’s maximum effective range because this extra, intense light overwhelms and somewhat confuses the laser’s light sensor. Even waiting for clouds to block the sun can help, as can lazing from a shadow into a shadow, but only marginally. The very longest ranging can be achieved in overcast, or at dusk — that’s when I’ve had some lasers range far beyond their official maximum.


DENSITY: The thicker and more impervious your target, the better. If you must laze foliage, go for a thick clump of broad leaves rather than an equal area of pine needles which may diffuse laser light. A solid cliff face is better yet. If you’re lazing in grassland, don’t laze on the grass itself, but onto an exposed spot of earth. Think of your laser as a
flashlight, and you prefer to shine it at something that will completely block its light beam.