Silencer Co Radius.....Someone explain to me the theory...

[Bocephus]

Since getting into thermal, the whole judging distance (like I knew), has been an issue, not a big one, but it still lingers there.

From what I see, most guys who are heavy into night hunting seem to be running the SilencerCo Radius, or something to the like. But my head is having a hard time understand the geometry, physics, whatever you want to call it behind the process or theory on how it works.

I will try to explain my hang up, and you all correct me where I went wrong. I will say I'm not questioning the product either, I think enough people swear by it for it to be flawed, I just don't understand it.

So here I go. From what I see, the LRF mounts to the side of the rifle (in most cases from pics I see), and the theory is you sight that in with your optic. Much like sighting in your weapon sight for the first time. But here's where I'm lost. The LRF shoots a straight line beam from the side of the weapon to meet up with your optics cross hairs at whatever desired intersection point. For that to happen, lets say its mounted on the left side of your rifle, the beam needs to travel "cockeyed" right and up or whatever to meet your line of sight of the reticle at desired intersection point. Anything after that the beam keeps traveling right while your line of sight stays true.

So if you sight this in for say 200 yards, where is that beam at 700 yards, and how do you know if your hitting your desired object when it comes back with a reading?

Any info to correct my understanding would be greatly appreciated!

Thanks.

 

[Curly Shuffle]

I don’t know anyone with thermal that uses a range finder, they, I just use the scope and when we walk up on something we just know it is somewhere between 30 and 100 yards or so. We adjust accordingly. I would imagine it is the same for night vision. The only two times I used them we were around fifty yards away. BANG BANG!!

 

[Curly Shuffle]

I looked it up and pasted this. From what I read it is used just to find the target/distance? For shooting both have to be set to zero then scope is dialed in for distance. BANG BANG!!




Review: SilencerCo Radius Rangefinder
by Tom Beckstrand | June 20th, 2016 | Photos by Mark Fingar 0

The Radius comes packaged with a rangefinding unit, a pressure switch, orange reflective tape to help zero, a zero target and an owner’s manual.

I expect firearm-mounted rangefinders to become equally crucial on sniper rifles. When mounted on a rifle, rangefinders can be employed much faster than handheld models. There is no need to break from our shooting position, grab the rangefinder, range the target and then get back behind the rifle. All that gun juggling takes time, and time lets Charlie slip away. Not my war, but you get the idea.

Snipers should pay attention to the firearm-mounted rangefinder trend. LE snipers might think that rangefinders don’t really apply to them, and that assumption would be incorrect. If the rifle is zeroed at 100 yards and the sniper needs to slip a bullet through a window that’s only been cracked open an inch, knowing the precise distance to the opening becomes crucial.

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The SilencerCo Radius represents the first time this type of rangefinder has been within reach of the mainstream long-gun community, and boy have they set the bar high. The SilencerCo Radius is 5 inches long, 3 inches wide and 2 inches deep. It can be mounted above the scope or on the side of the forend.

Mounting the laser up top is the simplest solution because all it takes is a rail section on top of the forward-most scope ring. Mounting to the side of the rifle can be equally simple if the rifle has sections of rail located there.

If the Radius is mounted to the left side of the forend, the display is visible from the shooter’s non-dominant eye while behind the rifle. However, the Radius blocks some of the shooter’s field of view in this location.

I placed the SilencerCo Radius above the scope and had no problem zeroing it. Once mounted, I turned on the visible laser and moved the laser until it was the correct height above the crosshair. As long as we can clearly see our crosshair and the red dot, the distance to the “zeroing” target doesn’t matter — 30 yards works as well as 200 yards.

Since our line of sight has no trajectory, and neither does a laser beam, make sure the distance between the two on the target board corresponds to the distance between the center of the scope and the opening for the visible laser on the Radius. The Radius mounted on my rifle was 3 inches above my line of sight.

The SilencerCo Radius will work with any scope, but shooters who hold instead of dial will be faster at multiple target engagements. Weapon-mounted rangefinders get zeroed with our turrets dialed to zero. In order for the two to work together, the rangefinder requires that all targets get “ranged” with the elevation turret zeroed out.

Snipers that dial will need to zero their turret, range the target and then dial prior to shooting. When that sniper moves to a new target, he must return the elevation turret to zero prior to ranging the new target. The sniper that holds never touches the turret anyway, so he can just range the target, holdover, shoot and move to the next one.

Getting the test rifle set up with the Radius took about five minutes and zeroing took another five to 10 minutes. The majority of that time was spent putting up the zeroing target that comes with the Radius.

The unit is small and comes with an integral quick-detach lever that adjusts to tightly fit the rail on which it’s mounted.

Once zeroed, I moved to the 1,000-yard range and ranged steel targets to see if the Radius picked them up. It was an overcast day, 54 degrees and 46 percent humidity. I had no problems hitting all the steel plates out to 1,000 yards. The targets were 18 inches wide and 30 inches tall, so I didn’t expect any problems.

For the next round, I only aimed at the head portion of the steel targets. These measured 6 inches by 6 inches. Once again, the SilencerCo Radius made it easy. I moved from the head plates to the dirt berm behind the 1,000-yard target, and the Radius gave the range for that, too. I moved from there to the stand of trees behind the berm, which also worked with ease. The trees were my last hope to defeat the Radius, so I packed up and called it a day.


The SilencerCo Radius is a fantastic piece of gear for any long-range shooter. It allows the shooter to remain behind the rifle as they work from one unknown distance to another. It also allows civilian shooters and snipers a cost-effective way to accurately range targets at night. Once zeroed, the SilencerCo Radius is high enough to see over clip-on night vision equipment that’s in front of the objective lens. Police departments and nighttime hog hunters will both benefit from this new capability.

GALLERY: SilencerCo Radius Rangefinder
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[Bocephus]

Correct Curly - I'm not looking to zero my rifle and weapon sight. My question stems around the theory of lining up the LRF when using thermal, and knowing you are ranging your intended target. I posted in a few places, and I have a better understanding now, and that is you sight the LRF in parallel with your weapon sight. Which to me still seems very easy to "miss" your target you are wanting to range at 700+ yards, but I think for most, it gets the job does as intended. I think with NV from what I understand, this is much easier because you can turn on the laser and see what you are pointing at.

And from the different forums, a lot of the guys heavy into night hunting use a range finder.

 

[Brian Shaffer]

Bocephus, that is a good question and the problem goes deeper than that. You want to use it for thermal. Most folks are not going to mount the Radius on their thermal scope. They are going to mount it on the handguard. Handguards torque with pressure. Barrels torque with pressure. You never rest your barrel when zeroing, right, because it will change the POI. Same will happen with the Radius on the handguard. Where you THINK you are ranging may not be the place you are ranging.

Have you used a LRF before? Have you tried to range a cow at 500 yards and gotten an 800 yard reading? Simple, it can be easy to not range what you think you are ranging if the beam is just a tad off from the crosshairs of the rangefinder. In the cow example, you ended up shooting the beam beyond the cow where it hit something in the distance.

Well, the Radius going to help you out with that. It isn't going to give you a single range. You will get not 1, not 2, but THREE ranges, a primary and two secondary and then you must guess which is the most correct, if any.

They started out at $1000 and have sold for as little as $360 this past year.

 

[wigwamitus]

haha, I am actually going thru this process right now ... I didn't know any one was interested ... but I will post the details in my practicing thread.

 

[Bocephus]

Brian - my usage of range finders has been for bow hunting, and the occasional jacking around looking at a cow from 500 yards like you mention, haha. And yes, its very easy to miss your target you are ranging, thus again driving questions about using this range finder at night for guys with thermal. From my understanding after getting various replies is that it runs in parallel with your barrel. If that is the case, and your rifle is sighted in at 100 yards with your optic, where you are pointing that optic at 1000 yards, your barrel is going to be no where close; right????

That's what has me confused about this process. Thermal isn't exactly a "precision" instrument. Case in point, I have a buddy who has one of these on his rifle, with a thermal mounted on top. One of our stands we hunt is an elevated platform on between two grain bins looking over several fields. When we have a yote coming in from a far, he's always reading distances on the dogs. My mind instantly goes "how the hell do you know if you are even close to that dog and not just reading the ground".

I'm probably over analyzing an issue that isn't there, but having the hardest damn time fully grasping the concept.

 

[Brian Shaffer]

You are and you are not. Your concerns are valid. The question then is that when using thermal, does it matter what the ranging is if it is too far for you to shoot anyway. Do you care if the data show 400 versus 450 yards if you aren't pulling the trigger? You just need to know when the targets are reliably inside your comfortable shooting distance for thermal, which is probably inside 200 yards.

You DON'T zero with the barrel, but with where the scope is looking. If you dial in windange or elevation changes, you won't be looking in the same place as the Radius is zero'd. This is more an issue with daylight scopes, but relevant to understanding inherent issues.

Thermal can be very precise. It just depends on the scope and the shooter, though it can be hard to zero tighter than the area underneath the (usually) thick crosshairs.

Since most people do not zero their Radius to their thermal scope using night vision, it can be tough to know just exactly how well co-witnessed the Radius is with the thermal scope. The laser beam at 100 yards may be 2-4" in size. Maybe you are shining it to a point that your crosshairs just catch the left edge of it, but you don't know. All you know is the paper is at 100 yards and the readout says 100, so you assume it is co-witnessed.I have not see the Radius' laser beam to know for sure, but I have with other rangefinders. Plus there is some splash around the hot point. Add that to the fact that the beam is not co-witnessed through the scope but along side of it and so you can get some interesting problems at distance on whether the beam and crosshair are really on the same thing or not.

 

[wigwamitus]

Here's where I'm at right now with the RAPTAR.

Practicing with Night Vision | Page 35 | Lone Star Boars

 

[Bocephus]

You are absolutely correct in the fact that it doesn't matter because I will not shoot over 200 at night time. This is more from a pure curiosity stand point on the theory behind it. Very good info you have provided above, and I do appreciate the feedback. I also should have generalized with I was talking about precision with thermals, yes, I do agree that I'm sure they can become precision instruments. I think in general, if a guy can hit a hand warmer at "x" yards he is sighting in for, they usually call it good. Versus trying to stack bullets in the same hole.

Appreciate the response and good conversation on it.

 

[wigwamitus]

In open terrain, I also like to know how far away hogs are to help plan stalk route. Not just to shoot. But, accuracy does not have to be inside 1 meter for that.
For long distance with thermal, I think you have to go with clipons and if you do, then you can co-witness the laser to the reticle without thermal involved, then you mount the thermal and go.

 

[Bocephus]

Appreciate that info Wigwamitus, I read your other post, its starting to make more sense on how to accomplish it.