The Long Rangers
By Darin Cooper
©Western Hunter Magazine
An in-depth look at two premier ballistic rangefinders - And both are available at Len Backus' Long Range Hunting Store. G7 BR2500 Sig Kilo 2400

Among the masses of rangefinders available, a pair of them stands heads and shoulders above the rest in the eyes of serious long-range shooters: 1) the second-generation G7 BR2, and 2) the recently released Sig KILO 2400 ABS. There are laser rangefinders that range farther, and some with better optics, but I'm not aware of any consumer-grade rangefinders that combine range capabilities exceeding 1500 yards with on-board, weather-sensing ballistic engines accurate to 1400+ yards.


Both units can store multiple custom profiles to cover each rifle and bullet combination you use. The on-board sensors read atmospheric conditions when ranging so air density can be factored into the firing solution. The weather sensors are critical at ranges beyond 600 yards where temperature and altitude become significant factors in bullet trajectory.

I've used the G7 BR2 for 15 months and the Sig KILO 2400 for about six months. I've bowhunted, rifle hunted, and shot several long-range, precision rifle matches with both, so I can attest to their accuracy, durability, strengths and weaknesses, and I can provide some insight on their usage in the field.


The Sig KILO 2400 ABS taking some punishment on the author's hip at a Precision Rifle Series (PRS) match.
Prior to ballistic rangefinders, a long-range shooter needed a weather meter, a high-performance laser rangefinder, and a ballistic app to calculate an accurate firing solution. Those tools yield an accurate solution, but you'll spend far more time measuring, juggling devices, and typing in data to get it. Wasted time in a hunting situation often leads to wasted opportunities.

One reading from these rangefinders is sufficient for me to make first-round hits on steel targets out to 1000 yards if I make a good wind call and do my part behind the trigger. A wind-meter still comes in handy at times, and conveniently, one is included with the Sig Kilo 2400ABS.


The Sig KILO 2400 ships as a well-equipped kit that includes a wind meter, tripod adapter, belt pouch, pen and screen stylus, a lanyard, instructions, two extra batteries, and a padded case to hold it all.

Drawing Comparisons
There are some obvious differences between the two units, but I'll dig much deeper to point out subtle nuances that may make one unit or the other the best choice for you. I'll also do my best to distill marketing hype down to the features that apply to hunting.

Size & Ergonomics: The size difference between the two is apparent when you hold and compare them side by side. The G7 is much larger, and the form factor diverges from the typical rangefinder shape we (especially bowhunters) have grown accustomed to. The G7 is designed to operate in the horizontal orientation, while the svelte Sig is gripped vertically. The KILO 2400 is so compact my pinky finger hunts around for real estate on the short grip section of the housing.


The G7 lends itself better to two-handed operation when using the arrow keys to adjust display brightness or to toggle wind values.

The ranging buttons are well laid out on both rangefinders, allowing for ambidextrous ranging, but I find myself using my off-hand to manipulate the arrow keys on the left side of the G7 as a matter of comfort. The G7's arrow-keys are used to adjust display brightness, wind values, and to select parameters in programming mode. I can easily range targets at 700+ yards using one hand with either unit.

I've packed each of these units on several multi-day outings. I don't use the carrying pouches included with either rangefinder. I prefer Sig's form-factor because it fits in a traditional rangefinder pouch on my hip. It's not so much that it's better in this regard, but it's what I'm accustomed to. I carry the larger G7 in a binocular chest harness, which forces me to wear my binoculars slung over the shoulder.


Although I prefer the Sig's form factor, it could use a slightly longer housing to better protect and shade the objective lens and provide more room for average to large hands.

Tripod Usage: When you're trying to get pinpoint readings on distant targets, it's always best to steady the rangefinder against something, or better yet, mount it on a tripod. The G7 has a built in ¼-20 threaded hole for attaching tripod QD plates. The Sig includes a machined aluminum tripod adapter sleeve the rangefinder slips snugly into. The G7's built-in mount eliminates the possibility of losing or leaving the adapter at home, is quicker to deploy, and doesn't add bulk. Both tripod mounts are sturdy and effective, but the Sig mount is cumbersome to use and will require a brief wrestling match to dislodge the mount when you're done with it. The G7 wins this category hands-down.


The G7's built-in ¼-20 mount makes tripod use simple and convenient.

Optics: Both units have 7x optics that are good by stand-alone rangefinder standards. The G7 has a slightly larger objective and eyepiece that may provide a slight brightness advantage over the Sig. The effective magnification and field of view are very similar in both units. The eye-relief and focus controls are located on the eyepieces of both rangefinders. The G7 controls are larger and easier to rotate, but are also a bit more prone to move inadvertently when hiking and hunting.

Displays: When the G7 display is activated, the backlit LCD has a red background that can obscure the view when the brightness is set too high for the ambient light. The Sig's OLED display background is cleaner with better definition of the aiming reticle, text, and symbols. The Sig can be set to auto adjust brightness based on the ambient light it senses. The G7 has four manual brightness levels that are easily set with the left arrow buttons. The Sig's auto brightness feature is more convenient and works well enough that I've never used its nine manual display settings. I prefer the Sig's auto-dimming OLED display.


On the left, you can see the faint red band running horizontally through the G7 display. If brightness was adjusted down to the next level, it wouldn't be noticeable. The G7 BR2 renders color more naturally compared to the greenish color cast of the Sig KILO optical system.

Ranging: This is what really matters most and I'll tell you straight-up, these are two of the most impressive rangefinders I've ever used…even without considering their ballistic wizardry. I've spent (wasted) a bunch of money on lesser units over the last ten years and most of them frustrated me more often than they impressed. We have finally entered an era where rangefinders outperform our needs…Hallelujah!

G7 BR2
This unit will effectively range animals and non-reflective terrain (hillsides, trees, bushes) out to its 1400-yard ballistic limit and then some. The G7 will typically pick up reflective targets like rocks and steeper hillsides out to about 1800 yards.

However, it will only provide a ballistic hold-over solution out to 1400 yards. To some, that might seem like a deal breaker, but for hunters, it shouldn't be much of a factor. It's rare that someone has the experience, ability, equipment, and ideal conditions required to take an "ethical" shot at ranges beyond 1400 yards or even remotely approaching it.

Even if you are capable, the fact that the bullet will be in flight for two-plus seconds on its way to the target should provide enough reason to stalk closer. The G7 has more than enough ranging horsepower for ethical long-range hunters.

The G7 BR2 has four ranging modes to help filter foreground and background interference so you get the range to your target and not its surroundings. The Nearest (N) and Farthest (F) are the most useful for target discrimination. Users should get proficient at changing these through the mode button. Farthest mode will allow you to range better in rainy conditions and through light fog, haze, grass, and brush.

One outstanding feature that sets the G7 BR2 apart from the Sig is its ability to provide a ballistic hold-over solution that works with custom, Ballistic Drop Compensation (BDC) turrets that are popular with hunters and scope manufacturers. Most hunters are far more comfortable thinking in yards to the target than adjusting their scope dials in minutes of angle (MOA), milliradians (MRAD or MIL), or inches of drop. A BDC-yardage turret has laser-etched or printed yardage increments on the elevation knob that are calibrated to the gun and ammunition.

BDC-yardage turrets are limited by the fact that they are only correct for one specific air density, bullet, and velocity. The error potential is minor at ranges out to 600 yards. However, a change of 20 degrees and 2000 feet 0 elevation can cause a 10" impact change at 1000 yards. That kind of environmental change can easily be encountered over the course of a single day's hunt.

To compensate, the G7 BR2 reads the current atmosphere and provides a "Dial-To" yardage that is different than the actual distance so you can still hit targets using a BDC turret, regardless of the conditions it's calibrated for. This feature is extremely useful, and I dare say, a necessity if you have a BDC yardage turret and plan on shooting beyond 600 yards. I hunt with guys who use BDC turrets, so I'll likely have a G7 with me on most of my hunts.


Insert BDC-Yardage Turret: If you or your hunting partner have a BDC-yardage turret atop your scope, you need a G7 rangefinder. The Sig won't compute BDC - yardage…However, the numbers in fine print at the bottom of the knob are MOA and the G7 and KILO 2400 will gladly give you a firing solution in that language if you're willing to take that angle.

This article was originally published by our friends at Elk Hunter and Western Hunter magazines. They are among the select few print hunting magazines I read these days. I think you would like them, too. To learn more about them, CLICK HERE
-Len Backus-

Sig KILO 2400
The KILO 2400's ballistic solver and ranging capabilities are remarkable for a non-military device priced at $1500. I've ranged hillsides 2500 yards in bright sunshine and over 3000 yards in more favorable overcast and lowlight conditions. I've ranged rocks and brush in heavy rain at over 2200 yards. I can laser deer and elk at 1500 yards in most conditions.

The sophisticated ballistic engine developed by Applied Ballistics LLC and their chief ballistician, Brian Litz, factors in atmospherics (pressure, temperature, humidity) and more sophisticated factors such as Coriolis effect, which is a function of your location, direction of fire, and the Earth's rotational velocity. The KILO also calculates spin-drift, caused by gyroscopic effects of a spinning bullet in flight, and aerodynamic jump, which is a bullet's vertical displacement caused by a crosswind interacting with a spinning object. There are also features that account for muzzle velocity changes due to powder temperature sensitivity and turret corrections if your turrets don't track exactly to scale. These factors all combine to calculate a precise firing solution for anything you can range.


Author using the KILO 2400's wind-meter that's included in the kit.

That kind of reach and technology is fantastic for extreme long range (ELR) shooting competitions or for stretching the limits of you and your equipment in practice. The Sig syncs with the GPS in your smartphone to update location via Bluetooth for Coriolis calculations. Coriolis, spin-drift, aerodynamic jump, and humidity all have minor effects on trajectory and are usually negligible unless shooting at ranges over 1000 yards. Even at extreme range, the secondary factors accounted for by the Sig KILO 2400 are minor compared to the error caused by misjudging wind speed by as little as 2 mph.

With that in mind, it's hard to fault the designers of the G7 BR2 for ignoring them. Still, the fact that they're figured into the equation, ensures you get the most accurate firing solution possible. If you're keeping score, when I've tested the two head to head, the G7 BR2 and Sig KILO 2400 almost always predict a firing solution within .1 MRAD or about 3/8 MOA of one another out to 1400 yards. That's better than the precision most rifles are capable of at 100 yards.

Sig KILO App
Purchase of a Sig KILO 2400 also entitles you to download the free phone app that works with Android and IOS (Apple) platforms. You need the app to create and sync your rifle profiles with the rangefinder.

The app contains an extensive library of more than 530 bullets. Each entry is complete with the important physical data including G1 and G7 ballistic coefficients. Many of the bullets also include custom ballistic drag curves that replace your BC. These are derived from live-fire experiments conducted at an independent (not the bullet manufacturer) lab by Applied Ballistics. The data built into the Sig KILO's library has proven more accurate than using published or advertised BC's in my experience.


Screen shots from the app are shown here. Home screen, bullet selection, and profile editor on the far right.

The app isn't necessary for in-the-field ranging, but it does offer some nice utilities. One of my favorite features is the Heads-Up Display (HUD). To use it, set your phone where it can be seen while you're on the rifle and enter HUD mode in the app. As the range button is pushed on the KILO 2400, the HUD on your phone will display the firing solution with elevation and wind corrections. The HUD also displays current temperature, pressure, density-altitude, and the bullet's predicted velocity and energy at the target you ranged.

You can adjust the wind speed within the app or override atmospheric data in the "Environment" screen or calculate leads for moving targets on the "Target" screen. The wind meter included with the KILO 2400 sends actual wind values to the rangefinder when attached to your smartphone, but you'll need to manually enter the wind's direction. The wind meter is a great way to start out and learn what various wind speeds look and feel like.


The Heads-Up Display is a great way to send a firing solution to your partner while you range for him without making a sound.

The remote "Range" button is another useful feature in the HUD view when ranging off a tripod so the rangefinder isn't disturbed by pushing the button manually. The KILO still needs to be aimed to ensure the laser is on target, but the app can fire the laser so the KILO stays perfectly steady, like using a remote camera shutter release with a long telephoto lens. Again, the Sig KILO app isn't required in the field because you will see the same firing solution in the rangefinder's display, but it can be useful.


The remote range button is a good way to activate the rangefinder when lasing distant targets on a tripod. It eliminates movement caused by pressing the rangefinder button.

I'm primarily a bowhunter with a serious rifle habit. Therefore, one of the most important functions each of these units needs to provide is accurate, angle-compensated ranges for bowhunting. Both are capable when set in the proper mode.

For the G7 BR2, set the rangefinder to Range Only mode in the profile selection menu. The KILO 2400 needs to be set to Angle Modified Range (AMR).

Surprisingly, both rangefinders jump around a bit on close targets by +/- ½ yard. From that, I conclude they're only accurate to within a yard or so at short range on a single reading. That's a little disappointing for an archer considering they'll both range the same rock at 1381 yards if aimed properly. I would expect them to give exact, repeatable measurements on a 3D target at bow range.

Both are adequate for bowhunting, but for target archery, I'd prefer repeatable results at 0.1 or 0.2-yard resolution. I suspect there's a tradeoff in short-range resolution when tuning the receiver sensitivity to detect light coming back from objects over a mile away. It's hard to complain about +/- ½ yard error with a straight face. I should probably just be happy the lasers don't melt my 3D target.


I was toting the G7 BR2 on my hip and used it to range this rutting muley at 64 yards on a Montana bowhunt last fall.

One fear many people face with high-tech gadgetry is that it will be too complex to use effectively. Breathe easy; both the Sig KILO 2400 and G7 BR2 rangefinders come with well-written manuals, and the menus on the devices are easy enough to navigate for a novice. In fact, most of you can probably set up either device correctly without instructions if you know your rifle and bullet parameters. I still keep the laminated quick reference card in my binocular pouch when I'm using the BR2 just in case I forget how to access a specific feature.

The Sig's companion ballistic app is simple to use and it syncs reliably with my iPhone via Bluetooth. A friend reports similar, trouble-free use with his Android and his KILO 2400. You don't need cell service or internet to make rifle profile updates. The app actually simplifies the process of building and loading profiles because it's easier for me to type and edit fields on my phone. Furthermore, the on-board bullet library has all the ballistic data necessary for most bullets so you won't have to look it up or guess at BC or bullet length.


It never hurts to read the instructions. The G7 provides a laminated quick reference card.

All programming on either rangefinder can be handled at home, well before your hunt. In the field, you may need to change display brightness or select a different gun profile, but those features are readily accessible and can be mastered with little effort. Applied Ballistics has detailed instructions on their website for the KILO app that describe input variables, installation, and syncing via Bluetooth.

Rifle Setup & Validation
Both the G7 and Sig have amazing capabilities, but you must test them to confirm your programmed inputs are providing accurate solutions. You should always verify muzzle velocity and ballistic coefficient (BC) by shooting targets at four different ranges, including your 100-yard zero.
A chronograph will give you the best starting point for muzzle velocity, but in my experience, you still need to validate velocity input through live-fire. Have a friend sit directly behind you to spot impacts with a spotting scope to help you make corrections. Set a generously-sized target up with a berm as close behind it as possible so the dust signature from any shots off target will be easy to read.

Calibration Tips:
1) Always use a 100-yard zero… ALWAYS! When you zero at 100 yards, it won't matter if you're at sea level and zero degrees, or 10,000 feet and 80 degrees; your zero should hold. If it gets bumped, you can adjust the scope back to zero without influence from atmosphere. On the contrary, if you zero at 300, your zero will change with air density and re-zeroing under different conditions will cause errors. You can still hunt with your turret dialed to 250 yards for quick offhand shooting. Use a G7 BC with modern, high-BC bullets or use a G1 BC with shorter-nosed, flat-based bullets and bullets with no boat tail. If using the KILO 2400, the custom curve will usually be the best option for BC.

2) After you have a solid zero, calibrate velocity by shooting targets at 300 and 600 yards. Modify only the velocity input until the rangefinder gives hold-over in your preferred unit (MOA, MIL, inches, or a shoot-to range) that centers your impact group vertically at 300 yards. Next, fine tune your muzzle velocity at 600 yards until impacts are again centered vertically. BC has little effect on trajectory at these shorter ranges, so as long as it is reasonably close and your rifle is consistent, you should have no problem getting on target between 100 and 600 yards.

3) Next, calibrate BC to correct your elevation at long range. I typically do this between 1000-1200 yards. You may need to validate at shorter range with lower velocity cartridges and light-for-caliber bullets to avoid trans-sonic and subsonic velocity where BC won't predict drag accurately. As long as your bullet velocity is still above 1400 fps at the target, you should see consistent results. If you're shooting a .308 Win. and 150-grain bullets, you may need to calibrate BC below 1000 yards. Conversely, if you're shooting a .338 Lapua with 300-grain bullets, you may get a better calibration by truing BC at 1000 and 1500 yards.

If your impacts are 2 MOA low at 1000 yards, decrease the BC in increments of .005 in the rangefinder or app until it predicts a solution that is 2 MOA higher. Once you're on target at this distance, your BC is verified. BC's commonly require calibration adjustments of 3-10% up or down from advertised values. BC varies from published values due to measurement errors, muzzle velocity, barrel twist rate, and even bore diameter. Changing the BC should have very little effect on your impacts at 600 yards and closer. Truing the BC at long range allows for more accurate wind corrections even if you never intend to shoot beyond 500 yards, so it's still worth the effort to validate it.

What Could Be Improved?
: The top of the rangefinder housing should extend further forward to shade and protect the objective lens, and provide a larger grip area. A built-in ¼-20 tripod mounting location would be a significant improvement over the aluminum adapter. The Sig KILO app should be able to generate a table of ballistic data rather than just a single point solution. Target speed input unit would be more useful in MIL/s or MOA/s that can be directly measured in the riflescope or with the MIL grid in the rangefinder display. LOS or line of sight mode is a misnomer that can be confusing to the user. LOS distance typically indicates a ranging mode that doesn't compensate for angles of incline/decline. LOS mode does in fact compensate for inclination, despite what the literature states.

G7 BR2: Changing to a different profile takes too long. A buddy spotted a black bear last year feeding toward cover across the draw. I switched the G7 to his rifle profile that I had pre-built. It seemed like an eternity waiting for it to finish loading the new profile so I could range for him. It actually takes about 30 seconds to get back to ranging, but your buddy will swear it took twice that long. I'd prefer a smaller housing or a full binocular in a rangefinder of this size. Leica, Swarovski, and Bushnell all have ranging binoculars, and although none have the accompanying ballistic engine to compete with the G7 BR2 or Sig KILO 2400, I bet they're working on it.


Parting Shot
I don't think you can go wrong with either rangefinder. Both are fabulous improvements over conventional range-only systems. Choose the G7 BR2 without hesitation if you or your hunting partner utilize a BDC-yardage turret on your hunting rifles. If you prefer the smaller vertical rangefinder or need extreme long-range firing solutions, you can't go wrong with the Sig KILO 2400 ABS. Either will likely be the last rangefinder you ever need to buy, and a purchase you won't regret.


Hot off the truck! UPS dropped this bad boy off today. Even though I've only had one evening with the BR2500 before this went to print, it was enough to convince me that it's a solid upgrade in ranging performance over the BR2 with approximately 500 yards more reach.

As I prepare to send this article off to print, I've just laid my greedy hands on one of the first samples of the new G7 BR2500 ballistic rangefinder. As you might have guessed from its name, the laser hardware and ranging algorithms have been juiced up for better performance. I ranged non-reflective hillsides this evening out to 2300 yards and the new unit responded faster and more consistently at every distance than its predecessor.

I loaded a rifle profile for my 6x47 Lapua and the firing solutions were spot on with the KILO 2400 out to 1400 yards. The chassis is still the familiar G7 design, but under the hood, the beam divergence has been tightened up to .75x1.5 MRAD for improved long-range performance on game.

I'll follow up with my full take on the BR2500 for the next issue, but after kicking the tires I can confirm that it's a solid upgrade. If you were licking your chops over the BR2, the BR2500 is going to be just the ticket for you.

Both the G7 BR2500 and the Sig Kilo 2400 are available to purchase at Len Backus' Long Range Hunting Store.