Athlon Optics recently sent me their Cronus BTR Gen2 1-6×24. I was hoping to have it in time to teach the Stretz Tactical Two-Day Mid-Range (plus) Carbine Class and run it out to 600 yards, but it got to me just a little late. Nonetheless, I was able to run it through its paces over multiple range trips from seven to 200 yards and let some friends get some time behind it as well.
The Cronus BTR GEN2 UHD 1-6×24 with ATSR2 SFP IR MOA reticle was designed for 3-gun competition, tactical applications, and close-range hunting. The reticle has hold-over points for both bullet drop and wind compensation, and the ATSR2 reticle is designed for 68- and 69-grain BTHP 223 Rem/5.56mm NATO rounds.
The windage and elevation click value is 1/2 MOA. I personally would prefer 1/4 MOA clicks to the 1/2 for a more precise zero.
ATSR2 IR MOA Reticle
The scope features the ATSR2 illuminated MOA reticle, which is specifically optimized for standard 5.56 NATO / .223 Rem ballistics (calibrated around 68gr and 69gr BTHP duty and match ammo).
At 1x: The reticle gives you a crisp, prominent 1.4 MOA center red dot. Because it’s SFP, that dot doesn’t shrink, functioning exactly like a dedicated red dot sight for rapid, close-quarters target acquisition. The downside is that the best you can hope for is a 1.4″ group at 100, with competing optics in its class offering a 1 MOA dot.
At 6x: The reticle’s bullet drop compensation (BDC) and wind holds become active. It features open-center holdovers for 300, 400, 500, and 600 yards. The open-center design is a massive benefit; it prevents the reticle from cluttering or completely obstructing a standard 12-to-18-inch target at extended ranges. The lack of a 200-yard holdover does hinder bull’s-eye type precision at 200 without dialing.
Windage: Subtle horizontal hash marks provide holdovers for 5 mph and 10 mph crosswinds.
Note: Because this is an SFP scope, your BDC subtensions and wind holdovers are only accurate when dialed to the maximum 6x magnification.
Optical Performance
This is where Japanese manufacturing shines. The Cronus BTR Gen 2 utilizes UHD Extra-Low Dispersion (HD) glass with advanced fully multi-coated lenses.
Clarity and Distortion: The edge-to-edge clarity is phenomenal. There is virtually zero edge distortion or pincushion effect. When looking through the glass at 1x, the scope body practically disappears, leaving you with a true, flat, two-eyes-open shooting experience.
Light Transmission: Color contrast is deep and realistic. It handles harsh backlighting and low-light dawn/dusk environments exceptionally well without severe chromatic aberration (color fringing).
Eye Box and FOV: The eye box is incredibly forgiving at 1x, allowing for fast mounting and shooting from unconventional positions. It boasts a massive 106.9-foot field of view (FOV) at 100 yards on 1x, offering excellent situational awareness.
Turrets, Tracking, and Build Quality
Athlon put real work into upgrading the Gen 2 internals and external controls over the original generation.
Tactile Controls: The low-profile turrets feature highly audible, crisp, and distinct clicks. There is no “mush” when dialing.
Locking & Zero Stop: It features a highly reliable pull-to-turn locking turret system to ensure your dials don’t shift accidentally during hard use, running drills, or field transport. It also incorporates a precise zero-stop mechanism so you can instantly dial back to your base zero in pitch-black conditions.
Mechanics: Built from a single piece of 6061-T6 aircraft-grade aluminum with a standard 30mm tube, the optic is rated to withstand severe shock (up to 1,000G for 1,000 repetitions). The magnification ring is smooth, though it has enough mechanical resistance that you will likely want to install a throw lever for fast manipulation.
features
| Feature | Athlon Cronus BTR Gen 2 1-6×24 SFP |
| Tube Diameter | 30mm |
| Focal Plane | Second Focal Plane (SFP) |
| Reticle | ATSR2 IR MOA (Illuminated) |
| Field of View (100 yds) | 106.9 ft @ 1x |
| Origin | Made in Japan (LOW Factory) |
| Warranty | Athlon Lifetime Warranty |
The gun used for the review
I build a brand new upper for this review. The build consisted of a Centurion Arms 16″ RECCE Barrel (RB-16-BLST1), mid-length gas tube, Knight’s Armament rail, Colt upper and BCG, and SureFire muzzle brake.
The lower is a Daniel Defense with a Geissele SSA-E trigger and MagPul CTR stock. These barrel and trigger options have served me very well in past rifle builds when accuracy was the desired outcome.
Ammunition used
I used Hornady 223 Rem 75 gr BTHP Match Item #8026 for this review. I am a big fan of Hornady ammunition, and you can read a past article I did on my favorite carry ammo, the Critical Duty135 grain plus P.
ZEROING
The manual suggested a 100-yard zero and that you could use the center dot for 100 and 200 yards. The first sub-tension was for 300 yards. While initially working with NRA B8 bull’s-eyes, I wanted to be as precise and accurate as possible at 200, without dialing.
I initially held the 1.4 MOA center dot (slightly larger than competitors’ 1 MOA dot) at 12 o’clock of the bull’s-eye, and after a shot or two, I realized I could bracket the black of the B8 with the dot at 12 and the 300 tick mark at 6 to make up for no 200-yard hold.
the group sizes
Keeping in mind the center dot of the reticle is 1.4 MOA, I was happy with the groups that I got at 100 yards, which averaged 1 1/2″ – 2″ using mostly Hornady 75 grain BTHP .223 Match.
As a control, I received the same results using some 77-grain 5.56 from two other manufacturers. I did notice during an evening grouping exercise that with the center dot illuminated and the sun behind and to my right, the illuminated dot bloomed a little, and the groups were consistently 2″ compared to 1.5″ with the dot turned off.
Groups at 200 yielded 4″ consistently, using the bracketing method previously mentioned. While I didn’t try dialing at 200, that most likely would have yielded tighter groups since it would have been more precise than trying to keep the black of the B8 “bracketed”.
Final Verdict
The elephant in the room for any high-end 1-6x SFP scope is the Vortex Razor HD Gen II-E. The Razor has long been the gold standard for patrol and competition LPVOs. The Athlon Cronus BTR Gen 2 goes head-to-head with it optically, sharing the same glass pedigree, but generally hits the market at a significantly lower street price at roughly $999, compared to $1,200 for the Vortex.
If you are looking for an LPVO that prioritizes fundamental speed, repeatable tracking, and high-tier optical performance without the premium “clout tax” of other brands, the Athlon Cronus BTR Gen 2 1-6x SFP is an outstanding piece of kit. It cuts out the social media hype and delivers an elite, daylight-bright, 1x performance coupled with highly usable 6x holdovers that will easily handle serious work at mid-range distances.
