RANGE ESTIMATION PART I:
"That prairie dog is at precisely 327 yards...and next time you get to carry this sonofabitch!"
Rangefinders actually aren’t a brand new thing. They’ve been around for better than a century. Unfortunately, they were coincidence rangefinders, also known as stereoscopic or parallax rangefinders. These worked by triangulation, just as you would use with a compass, with a prismed lens on each end of a long tube with a central eyepiece. The longer the tube, the more accurate the rangefinder.
Sure, they worked great and could be accurate indeed, but you needed a nice battleship or an artillery battery to lug them around with. They weren’t very well suited for use by the average infantryman or hunter.
Years ago, before laser rangefinders, when pterodactyls ruled the skies, I actually had a commercial sporting coincidence rangefinder. It was about a foot long and light enough, but when it came down to ranging it performed in a manner experts refer to as a “big pain in the ass”. You absolutely needed a straight line to range on, and it seemed like you had to recalibrate the fool thing every other day.
Now, I have a laser rangefinder. Yes, despite all my preaching about not relying on things that use batteries in the field, I have and use a laser rangefinder all the time. But remember Murphy? A few years back, I lost my Bushnell rangefinder out in the middle of a hay field despite the aptly-named dummy cord. Long story.
Fortunately, this turned out to be a good thing. I replaced it with the Nikon ProStaff 550 and I am much happier with that rangefinder. It’s only rated to 550 yards, but I’ve occasionally gotten ranges out to 750 under good conditions with it. It’s light and compact and handy, measures for yards or meters (me and my furrin’ military rifle scopes), and also calculates actual ranges on up and down angles, always handy in the mountains. I can highly recommend it.
In hindsight, I would have gotten a 1200-yard model, but they cost about twice as much and it would have just been for playing with my toys. The average hunter has no business shooting beyond 300 yards, if that.
I’m not to person to explain the inner workings of any electronic device. There’s stuff like diodes, non-visible wavelengths, infrared spectrums, nano-seconds and nano-meters, and, I think, dilythium crystals involved. (Ach, she canno’ take it, Cap’n. The toilets are backed up in the warp drive now!) Ben says it’s magic, but I lean more towards sorcery.
Anyway, here are just a few observations I’ve noted from using a laser rangefinder for several years now, mostly in hunting situations. They apply to pretty much any laser rangefinder. I hope some of these notes may be of use to some of you. Just my opinion and observations though; worth what you paid for ‘em.
As with your rifle or binoculars, the steadier the better. I often carry a walking stick while antelope hunting out in the big wide open, and can brace the rangefinder on the top of that to steady it. Going prone, sitting down with your elbows on your knees, bracing on a fencepost, whatever is going to make it much easier to get a precise reading.
It can be hard to range an actual animal, especially as range increases, as their pelt kind of soaks up the laser light rather than reflecting it. I often find it’s more effective to laze a juniper, clump of sagebrush, big rock or patch of bare dirt in close proximity to the critter.
Reflectivity is a weird thing. They say the more reflective, the better. I’ve found that ain’t necessarily so. I have a helluva time lazing my own truck, which is dark blue. I can laze and laze, trying different areas and the shady side, and get no reading off it. An instant later I can laze my range bag sitting on the ground near the truck or a nearby sagebrush and get a good reading right off the bat.
In bright sunlight, a rangefinder loses a bit of performance. On the other end of the spectrum, fog and mist disperses the laser and degrades performance to varying degrees. Dropping your rangefinder down a steep, rocky slope into a mountain stream really degrades performance.
Rangefinders work well in the dark. Unfortunately, the commercial models have an LED read-out inside the tube which you can’t see in the dark. I’ve found I can laze in very little light, then point the rangefinder at the sky and be able to read the LED against that lighter backdrop. Thus I can set up on my shooting position long before daylight and laze various objects to determine general ranges and have a pretty good idea of what I’m dealing with well before shooting light rolls around.
Of course, I’m not talking an overcast moonless night when it’s blacker than the inside of a cat; you have to be able to see what you’re lasing too. You have to have some light. This paragraph just made me think I should try using my rangefinder under a full moon some night. I’ll bet it would work. Update at a later time.
In a tactical situation, however, it should be noted that laser rangefinders show up bright and clear to someone with night vision device, pointing a straight line right back to your location.
While laser rangefinders work just fine in the dark, most commercial models have an unlit LED readout. While you may be able to laze the target, accurately, you can’t read what it says. In these situations, you can laze the target, then raise the rangefinder up to the sky to be able to read the LED numbers against the lighter background.
Usually, you cannot laze a game animal directly at a distance due to the non-reflectivity of it’s hair. The solution is to laze something very close to the actual target to get the range. We have a lot of dark green juniper bushes where I hunt and I find I can laze these quite well when nothing else seems to work.
Angle has some effect, too. You want to try to laze something as close to 90-degrees flat on as you can. Like a bullet ricocheting at a flat angle, the laser kind of can too.
The more solid the object ranged the better. If you have a choice of say an exposed rock, a juniper, and a clump of sagebrush you’d obviously try to laze the rock first since it will reflect the most light without diffusing it like the multiple small branches of a sagebrush.
Tall grass between you and the target can be a pain in the ass, too. You have to make sure you’re high enough so that the laser doesn’t hit those barely visible stalks and give a false reading.
A field of fresh snow is also a problem. Look for some kind of dark object like a tree, bush, or dead Commie which stands out in sharp contrast to laze.
One of the best things you can do with your rangefinder is to just carry it along with you on your walks. Estimate the distance to some point by eye, and then check the range with the laser to see how accurate (or inaccurate) you are. Constant practice playing like this will do wonders for calibrating your own Mk. I Mod 0 Eyeball if you have to estimate range the old-fashioned way someday.
I don’t know if this is worth anything, but I am more used to hunting wide open spaces so I tend to greatly over-estimate ranges when I’m in the dark timber high up bow hunting. I look at a certain tree up ahead along the trail and think, “That’s about 40 yards.” Nope. Nikon says 23. D’-oh! In the big wide open, however, I tend to under estimate range. That’s why it’s so good to take your rangefinder along on your hikes and test yourself.