Review: SilencerCo Radius Rangefinder

Review: SilencerCo Radius Rangefinder

Waterproof, shock resistant and capable to a mile

The readout on the robot-looking apparatus atop my 700P LTR rifle read 608 yards. I dialed the Nightforce ATACR's turret and settled in for a shot. Me being me I was optimistic, and the head portion of the Action Targets steel torso tempted. My rifle is extraordinarily accurate; my ability to judge wind less so, and my first 168-grain A-Max bullet whiskered just past the square-ish steel noggin. Adding another half-minute of wind to my previous two-minute hold, I squeezed off two more shots in quick succession. They clanged into the head just over an inch apart.


As you've likely guessed, the afore-mentioned ranging unit mounted above my riflescope was the SilencerCo Radius, an on-board, rifle-mounted laser device from SilencerCo Weapons Research. While properly mounting it and getting it co-aligned with your scope takes some study, it's compact, capable and admirably adaptable. Once figured out, it's user-friendly too.

Inventive riflemen with a knack with a welder, milling machine, or chewing gum and paper clips have been improvising methods to attach a rangefinder to their rifle for years, and optics manufacturers such as Zeiss and Burris have engineered superbly capable—albeit heavy and cumbersome—riflescopes with integral rangefinders. However, DIY rangefinder mounts don't provide perfect co-alignment with your scope's crosshairs, and integral lasers are expensive and limited to just one rifle system. Innovative engineers at SilencerCo figured there was a better way.

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The Radius rangefinder mounts via QD throw lever anywhere on the rifle that an appropriate section of MIL-STD 1913 rail can be attached. Note the click-adjustable dials for elevation and windage alignment.

Retailing for just under a grand, the SilencerCo Radius offers several unprecedented features. It mounts via a quick-throw lever to any section of MIL-STD 1913 Picatinney rail, so it's not only easy to remove and stow while traveling or hiking, but it's quickly adaptable across a whole bevy of different rifles. Shooting a PRS match this weekend with your Proof Research 6.5 Creedmoor, and going coyote hunting the following weekend with your Remington 700 Varmint in .22-250? No problem.

First, you've got to have a section of rail solidly mounted to your rifle. Quad-rail AR-type rifles are ideal, but it's also easy to screw a section of rail to the handguard or fore-end of any other rifle. Or, you can do as I did and fit the rifles you want to use the Radius on with Nightforce rings and a Nightforce RAP (Ruggedized Accessory Platform) rail that serves as the top half of one ring. Similar setups can be had from other companies, too.


With the rail in place, clamp the SilencerCo Radius on. If the throw lever isn't as snug as you want, tighten the screw that the lever is mounted on until it's just right.

Next, it's time to align the rangefinder with the crosshairs in your scope. Make sure your rifle is perfectly sighted in before attempting alignment. (This should be obvious, but I didn't zero my rifle beforehand and had to run the whole process twice.) The SilencerCo Radius is fit with two click-adjustable dials, one up front just under the "eyes" adjusts elevation, and one at the rear left adjusts windage. Of vital importance, there's also a visible red laser that is factory aligned with the ranging laser, and each SilencerCo Radius unit comes with an alignment target and instructions.

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Two CR123A lithium batteries power the Radius for 12 hours of continuous ranging, and the compartment is waterproof and easily accessed for battery replacement.

The quick and dirty on the alignment process goes like this: measure the distance between the center of your scope and the visible laser lens, and pencil it onto the alignment target the appropriate distance above center. (If you've mounted the SilencerCo Radius to the side of an AR or whatnot, you'll need to make a couple of measurements and mark the appropriate dot to the side of the target's center.) Next, put the supplied reflective round sticker over your pencil dot. Tape the alignment target up downrange—SilencerCo recommends 20 to 100 yards away, with farther being better—and sight on the center of the target. Dial the windage and elevation wheels until the visible red laser dot is on the reflective sticker.


With that accomplished, the laser rangefinder and your line of sight are aligned parallel. You may be tempted to align the visible red laser dot centered on your crosshairs, but don't do it. The laser and your line of sight will converge to that point, and then diverge from there on out. Say the rangefinder laser is three inches from the center of your scope and you align it dead on your crosshairs at 50 yards. At 100 yards, it will then be three inches off the other way. At 150 yards, six inches off. At 1,000 yards, 57 inches off. It's far better that the laser stays parallel to your line of sight, three inches away, all the way out.

Once I'd mounted and aligned the SilencerCo Radius on my rifle, I went prone with a bipod and sandbag and tested it for perfect alignment on a box at 202 yards. One really nice feature of the Radius is the constant scan mode, which provides constant feedback on whatever the scope is pointed at and eliminates the necessity to push a button every time you want an updated range. Amazingly, the SilencerCo Radius is rated to run in scan mode for 12 hours on a single set of CR123A lithium batteries.

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A visible red laser—the small glowing-red lens at center—enables easy rangefinder alignment with your scope's reticle.

After pushing the activation button twice quickly to put the rangefinder into scan mode, I aimed at the center of the 202-yard box, then the top edge, bottom edge, right edge, and left edge. Alignment was very close, but not quite perfect, since the rangefinder read past the target—213 yards—with my crosshairs on the right edge. Bringing it a single click to the left remedied that, after which the SilencerCo Radius read 202 on all edges but read past the box on all sides with the crosshairs held 1/2 MOA off the edge.

When on a big, easily read target, the SilencerCo Radius displays only one distance. However, when ranging small, difficult targets in the field, it provides readings from up to three different objects, displaying the strongest signal in large numbers, the second-strongest in small numbers in the upper center of the screen, and the least strong signal in small numbers in the lower center of the screen.

According to manufacturer's specs, the SilencerCo Radius' laser beam divergence is 0.5 mrad (1.75 MOA) by 1.85 mrad (6.35 MOA). Which way the oblong laser coverage is oriented is not specified.

To turn on the SilencerCo Radius, press the button on the left side (when the rangefinder is mounted on top of your rifle) of the rear face of the unit. As it powers up it will take a range measurement and display the result. To range again, press the same button again. To activate continuous ranging, double-tap the button. To turn the unit off, press and hold the power/range button for several seconds until the display goes blank.

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While it's a bit cumbersome atop your rifle, it's not unbearably so, and offers undeniable advantages. Ideally, the support eye reads the display while the shooter stays in position.

On the far side of the rear panel are two buttons. One swaps between yards and meters, and the other turns the visible red laser on and off.

The display itself is in a small sub panel, which may be oriented however necessary by loosening two knurled screws, pulling the panel off, rotating it as desired, and pushing it back on before screwing the knurled screws in again. Two buttons on the display panel make the display screen brighter or dimmer. SilencerCo warns against using the unit without the display screen in place and screwed down. In that condition, its electrical contacts are exposed and unprotected.

Interestingly, the battery compartment is separate and completely sealed off from the main unit. Both are waterproof and submersible to one meter, but if moisture happens to get inside the battery compartment while changing batteries or whatnot, the laser mechanism is protected.

The SilencerCo Radius automatically powers down after 30 minutes of inactivity, in order to preserve battery life should the unit be accidentally left on. To change batteries, simply pull the robust rubber battery compartment cover up, tug on the strap passing below the batteries to pop them up and out, and replace the rubber lid after inserting two fresh CR123A batteries.

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The display panel is easily removed and rotated to whatever orientation the shooter prefers. A pressure pad and hook-and-loop adhesives are included with each Radius unit, and can be used for remote activation. The short, broad screw is for blocking the visible red laser when hunting in areas where such are not legal.

A pressure pad with 18 inches of wire plugs into the side of the rangefinder and allows the user to activate the SilencerCo Radius without moving his or her hands from their shooting grip, and small round hook-and-loop adhesive patches are provided with each rangefinder to facilitate mounting it. Personally, I don't like wires wrapping hither and yon around my rifles, so I prefer to reach up and hit the button. Candidly, I almost always just double-tap it to put it into continuous ranging mode. That way I can focus on building a good position before glancing up at the display, and on executing a clean shot after dialing for the appropriate distance.

Which brings us to one element of the SilencerCo Radius that is critical to understand: The rangefinders alignment does not move with the crosshairs as you dial up for distance. If you prefer to dial for distance you've got to either dial back to your zero distance before ranging for the next shot, or use a reticle marked in MOA or mils and hold under the object you wish to range the same number as you dialed in for your previous target. For example, after dialing 13.25 MOA for 600 yards, I used my reticle and held 13.25 MOA under the next plate I wanted to shoot while ranging—whether that next plate was closer or farther—because that's the angle that the Radius now differed from my line of sight.

Really, it's best to simply shoot using a capable mrad or MOA reticle to hold over for distance, which keeps the SilencerCo Radius aligned with your center crosshairs at all times.

SilencerCo claims that the Radius is durable, which is easy to believe after examining the unit and its built-in, high-impact-resistant housing. Operational temperature ranges from extremes in practicality: it's rated for use from -20 degrees to 120 degrees Fahrenheit.

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While it's rated to range reflective targets to 1,760 yards—a full mile—in optimum low-light conditions, I found that in bright sunlight, the farthest reading I could obtain on an 18-inch steel plate painted white (a small but fairly reflective object) was a fraction past 1,000 yards.

Before hunting with a SilencerCo Radius mounted to your rifle, be sure and check your state's laws to ensure that electronics on your rifle are legal, and if they are legal, take it a step farther and research whether you're allowed to have a visible laser attached to your rifle. The solution is simple if not: each SilencerCo Radius comes with a screw-in laser blocker.

Is the SilencerCo Radius perfect? No, but for certain applications it comes pretty darned close. At 18 ounces, it adds a significant amount of weight to your rifle, and it makes your previously svelte shooter a bit cumbersome and top-heavy. For hunting anywhere outside of a box stand, I prefer a separate rangefinder, preferably one in a quality binocular. However, while I've never been a sniper, good sense suggests that having a Radius on your rifle could prove to be a game-changing asset for solo sniper overwatch type activities. As for competitive PRS type work, I definitely intend to give the Radius a whirl where legal.

Kudos to SilencerCo for another groundbreaking product and for introducing it to the market at a relatively affordable price.

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