TFB Review: Athlon HELOS BTR 4-20×50 IR FFP MOA Rifle Scope

Doug E
by Doug E
Athlon HELOS BTR Review 4-20x50mm

The Athlon HELOS BTR rifle scope series comes in a wide variety of magnifications and objective lens sizes, but the one I’ve tested and reviewed here is the 4-20x50mm version with a Minute Of Angle (MOA) reticle and turrets. MIL reticle and turrets are also an option on all but one in the HELOS BTR line, which is the 1-10x28mm that comes in an MOA bullet drop compensator reticle. The Athlon HELOS BTR as tested has the reticle located in the first focal plane (FFP), and the magnification level of 4-20x is a nice jumping off point for targets 50 yards and beyond.

Athlon Optics @ TFB:

I opted to mount the Athlon HELOS BTR atop my AR-15 chambered in 5.56x45mm.


The Athlon HELOS BTR rifle scope comes with a matte black finish and solid construction. The windage and elevation turrets are sturdy, tactile with adjustment, and lockable when not in use. I always like the locking turret feature, as well as the easy removal for zeroing that can be done with a flathead screwdriver or the ever-abundant pennies I keep picking up off the street.

Athlon HELOS MOA turrets.

The “IR” in the title stands for Illuminated Reticle, which is also a great feature for anyone looking to engage targets or game in low light. The outermost dial on the left turret is where the six brightness settings are located, and each level is interrupted by an off setting between each level which I also appreciate since I generally have an idea of what two levels of brightness I’ll need most often, but when in doubt, I keep the off setting between 1 and 6. Just inside the brightness setting is where the parallax adjustment is, which is easily adjusted from 10 to 500 yards, and then to infinity.

View through the Athlon HELOS BTR shortly after sunset, at 9x at 100 yards.

The Athlon APLR6 MOA reticle features a center crosshair, which is then spanned with 30 MOA of additional hashed lines to the left, right and up. Each hash mark is one MOA, with slightly longer hash marks at each 5 MOA interval. The line moving down from the crosshair affords 50 MOA hash marks, with Christmas Tree style windage dots that gradually increase from 5 to 20 MOA the farther down you look. I personally prefer this style, but your windage may vary.

Athlon HELOS BTR APLR6 reticle at 16x.
Athlon HELOS BTR APLR6 reticle at 4x. The reticle at its lowest magnification got a bit too thin but was still usable.


  • EYE RELIEF 3.6″
  • FOV @ 100 YDS 27.9 – 5.6 ft
  • LENGTH 13.3″
  • WEIGHT 27.6 oz


After having used two other optics from Athlon (reviews on the ARES and MIDAS), I wasn’t surprised that the image through the glass was superbly crisp and clean from edge to edge. The reticle’s numbers were a bit hard to read at 4x, but the crosshair still stood out enough. Moving the magnification up to 5 made the numbers in the reticle much easier to see, and naturally, with the First Focal Plane, were increasingly easier to see since each upturn of the dial increases the size of the reticle as shown in the photos above.


In my opening paragraph, I said that the Athlon HELOS BTR’s magnification range of 4-20x was a great starting point for targets 50 yards and beyond. I should clarify that my son thoroughly enjoyed blasting clay pigeons at 25 yards from the bench, then easily transitioned to shooting my MK Machining Covid target at 200 yards. Clearly, this magnification range is capable of shooting things closer than 50 yards, but from move-and-shoot competitions to hunting and self-defense standpoints, starting at 4x may be too much magnification at closer distances, but taking your time on stationary targets with no time limit affords less urgency. Heck, the parallax setting even dials down to 10 yards. While keeping the magnification at 4x, I shot the same Covid target at 200 yards offhand and managed five hits out of ten shots.

200 yards offhand

On my next range outings with the Athlon HELOS BTR, I focused on longer distances and put my target up at 500 yards. The wind was a bit tricky at first, but once I figured out what it was doing, I managed a 1.5-MOA group, if I don’t count the shot when the wind died and it actually hit where the crosshair was aimed as I held off for a mostly steady wind. That group was shot with Hornady’s Frontier 5.56 75 grain BTHP Match ammo.

Between the mirage and my camera, the image here doesn't look as good as it does to the naked eye. This is 500 yards at 18-20 power.

It seems that most of the rifle scopes I’ve tried have a pretty tiny eye box at the highest magnification, and I wasn’t surprised to find that the Athlon HELOS BTR had the same issue. While I was shooting at 500 yards, I dialed it back to the 18x power and shot using that sight picture, but if I wanted to glass in between shooting strings, I bumped it up to 20x magnification to eke out a bit more detail at distance.


I thoroughly enjoyed my time with the Athlon HELOS BTR 4-20×50 scope. After having done a bit more work to accurize my AR-15, it was satisfying to launch 5.56mm rounds with better accuracy than I had accomplished before in that caliber. I can still improve my part, but the Athlon HELOS scope really helped me see the target with great clarity and magnification, and the MOA reticle and turrets were simple to use. Each moving part on the HELOS was easily manipulated, and the controls were intuitive.

Athlon HELOS BTR 4-20x50mm made for a good DMR.

I highly recommend the Athlon HELOS BTR if it’s within your means and your desired role for your rifle. As I mentioned, this scope’s bottom end of 4x magnification may be a bit high if you’re looking for a do-it-all rifle to include CQB-style action and training but would be perfect on any rifle you want to reach out and touch something at distance. The Athlon HELOS BTR 4-20×50 has a list price of $749.99 for either the MOA or MIL versions. You can view all of Athlon’s HELOS line HERE for the rest of their magnification ratio options if the one I reviewed isn’t your preferred power range, or visit for their whole lineup of scopes, red dots, binoculars, rangefinders and accessories.

Check Prices on Athlon HELOS BTR 4-20x50 Scopes

What do you think about the Athlon HELOS BTR 4-20×50 scope? If you’ve already been using this one or another in the HELOS line, how has your experience been?

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Doug E
Doug E

Doug has been a firearms enthusiast since age 16 after getting to shoot with a friend. Since then he's taken many others out to the range for their first time. He is a husband, father, grandfather, police officer, outdoorsman, artist and a student of history. Doug has been a TFB reader from the start and is happy to be a contributor of content. Doug can be reached at battleshipgrey61 AT, or battleshipgrey61 on Instagram.

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  • KsKLR KsKLR on Sep 07, 2022

    These optics are a great value. I have the Helios 1+10 with a 34mn tube, and it's excellent. So good in fact that I pulled it off the AR-15 it was on and put it on the POF Revolution DI that I just purchased. This is a second focal plane scope, and I like it like that. At 1x the reticle and dot are very easy to pick up, even in low light with the illumination off. If it's far enough out that I need to range it, it's going to be on 10x anyway. I do have other scopes costing 4x this little Athlon, but that's the one that's on my #1 go- to rig. It's capable of everything from point blank out of the practical range of the.308.