Ozark Armament makes a 4x32 prism sight. It’s not hard to conjure up thoughts of the Trijicon ACOG. However, the Rhino 4x R4X-RGB does not cost what an ACOG costs.
I field-tested the Rhino R4X to assess the effectiveness of the BDC reticle, adjustment accuracy, illumination, mount, and watertightness.
During my hands-on work with the R4X, I learned that there are a lot of things I like about it and a few things I’m not that hot about.
Follow along to get the inside scoop.
Quick Overview...
What I Like: 4x prism sight
What I Don’t Like: Not waterproof
Best Uses: Recreational Use, Range Use, Training, Varmint Hunting, CQB, Close-Range, Best for .22 Rifles, Best for AR-15
- Magnification: 4x
- Objective Lens: 32 mm
- Eye Relief: 3.5”
- Field of View: 36.8 ft @ 100 yards
- Reticle: Rapid Range Reticle
- Adjustments: ¼ MOA
- Battery Life: TBD
- Dimensions: 6.5” (L) / 16 oz
- Mount: Integrated Picatinny mount
My Verdict: The Ozark Rhino 4x prism sight is a budget-friendly 4x32 alternative to the Trijicon ACOG. I really like the positive adjustments, the clean, red illumination, good mount, and integrated rails. Best for outdoor, daylight conditions, the Rhino 4x is an entry-level prism sight for budgets under $100.
Why Trust Me?
After hundreds of hours of hand-testing red dot sights in the field, at the range and on the hunt, and thousands more hours researching, writing, photographing and creating videos about them, I feel I have earned the title of expert when it comes to optics!
Optics are not just my passion, but also my full-time job!
I get my hands on as many of the optics I test as possible (through buying, borrowing or begging!) and run them through their paces to make sure they will perform out in field.
Check out our optics testing process here.
Over a decade of experience plinking, hunting and using firearms has been integral in putting together this Ozark Armament Rhino 4x review.
Who is the Ozark Armament Rhino 4x Best Suited to?
Overall, the Ozark Armament Rhino 4x R4X-RGB red dot sight is a budget prism scope. Its tricolor illumination, integrated rails, crisp 0.25 MOA adjustments, and sturdy mount are its best features.
I put the Rhino on an M&P 15/22 and a Bushmaster Patrolman. Of course, it's fantastic red dot for the .22 rifle, and it performed exceptionally out to 200 yards. That’s a long way to go for my lead and copper .22 rounds, but with the BDC reticle, I could holdover and hit steel. If you have a Pic rail, it’s good to go out of the box.
On the Patrolman with the front A2 sight (that I am not removing!), it was a little tricky. The performance was great, but the glaring shadow of the front sight was annoying. So, I’d say it’s best to use without back up sights or at least push them down. You’ll need to remove the rear sight anyway to get it far back to be in the eyebox with 3.5” of eye relief. It held up just fine with 5.56 mm rounds, and that’s what I recommend it for.
I think the illumination is good enough for outdoor use especially the black reticle, but it’s too bright for dark conditions.
With all that said, I think the Rhino 4x prism sight is good for daytime use for target or training and small game hunting applications on an AR-15. It is a budget optic, but it’s far cheaper than the name-brand 4x32 prism sights available.
How Does the Ozark Armament Rhino 4x Perform?
What I noticed right out of the box was the backwards adjustment markings. I’m accustomed to UP and RIGHT adjustments in the counterclockwise direction, and the Ozark Rhino red dot sight reflects this design as well. However, the R4X moves in UP and RIGHT adjustments in the clockwise direction.
The adjustments are referenced correctly for the way they work, so they're not actually 'backwards.' Follow the reference markings and you’ll get zeroed just fine. If you don’t, you’ll chase groups all over the paper until you figure it out.
This made for an easy sight-in process. I will admit that there were times I absent-mindedly made adjustments in the direction I’m accustomed to which was frustrating, but that’s no fault of the sight but mine alone.
I’m kind of impressed that I could actually use the Rhino 4x sight with two eyes open. Being magnified, it’s not really meant for use that way, but I found myself doing it rather easily.
The mount is actually good. I haven’t had movement during any of the range days. Finger-tighten them and then do another half turn with a flathead screwdriver for solid tension on the rail.
Overall, I’d say the Rhino 4x red dot sight is good for up to around a few hundred yards with 200 yards being the best for the small reticle and optical clarity. You can go further if you’re at the bench and have time to home in on the BDC holdovers. It has decent illumination, a quality mount, and a versatile design that allows for attaching other accessories.
Features & Benefits
4x Prism Sight
The Rhino 4x sight is a prism sight, so it uses a series of a prisms to bring a right-side up image to your eyes. Since the dot is not projected and reflected back to your eyes, it can be a better alternative to reflex sights for those with astigmatism.
I don’t have astigmatism, but I am far-sighted, so I do get some dot distortion with red dots. I like that I can use the diopter on the Rhino 4x sight to get a sharp image of the reticle while maintaining focus on the target and what’s downrange. I’d say the minimum focusing distance is about 20 feet.
The 4x magnification is nice and you don’t need a magnifier like you would with a 1x red dot sight. You can still see groupings on splatter targets through it to 50 yards and maybe 100 yards with good eyes.
The Rhino sight is about 6.5” long from the diopter to the extended sunshade cut of the objective bell. Thanks to this design, the objective lens is seated in the objective bell pretty deep to protect it and reduce glare and reflections.
There’s a lot of dioptric range on the diopter. I can’t find any specs for this feature, but there’s a good 7 mm worth of correction there. I used it, and you won’t find this on a reflex sight.
The eye relief is listed at 3.5”. I find this to be accurate. I removed the rear flip-up sight to bring it back further to acquire full eye relief. I like my adjustable stocks one click out, and the eye relief was great for my preferences.
Integrated Mount
The integrated mount feels heavy duty. It’s solid and heavy. It stays put when it's on the rail and I haven’t experienced any loosening or movement. It’s not removable, so the built-in mount is there for good.
It has a good height for a good weld on an MSR at a 1.41” optical axis height. No, you don’t want to pair this with a magnifier because it already has magnification. You don’t really co-witness with magnified scopes, but just in case you do, that 1.41” height will be a handy spec to know.
Those knobs are huge. They could present issues when you’re crawling or slicing the pie (doorways, hallways, corners, etc.), but if you’ve got a lot of gear on your rails anyways, I’d say the knobs aren’t at the top of your suspect list to be worried about.
Integrated Rails
I suppose you could mount whatever you want on these rails, there’s plenty of room for it all. You could put a laser on one side, a pistol sight on the top, and a flashlight on the other side if that’s your kind of thing.
I went straight for a pistol sight just because I could. I did have to zero the Vortex Venom red dot sight for this setup, and it was as straightforward as it could be. I’m not using the Venom to hit 100 yards, but it’s a great, non-magnified sight to have for those close-quarter shots. You do have to raise your weld, so it’s more like a chin-on-stock position – it’s high.
The top rail has four slots with enough of a mounting length for a micro RDS. The side rails have two slots, so you’ll need the right adapter mounts to get accessories on the side. I put a Streamlight flashlight on there just for the sake of it. Looks kind of cool, don’t you think?
BDC Reticle
Ozark has named this BDC reticle the Rapid Range Reticle. I suppose you could auto-range (range distance with a target of known size) with it but no reticle or subtension information is provided.
I’m assuming it’s calibrated for .223/5.56 mm rounds and is good for up to 600 yards with a 100-yard zero.
The only issue is that the BDC portion is so small that I can’t quite make out the holdovers quickly. I think I have pretty good vision, but even I will admit that it’s small. The part I find hard to differentiate is the 200 and 300-yard lines.
I actually like the thin crosshairs at the center of the reticle. It doesn’t take over the sight picture and FOV, and I can see how potentially effective the reticle would be for estimating range. But unless you have time or have a steady position to concentrate and find your holdovers, it’s slow to use in that sense.
The 0.25 MOA adjustments track accurately moving from 25 yards to sight in at 100 yards with my 5.56 rifle. Going out to 200 yards on steel was a non-issue. Hearing pings on steel always makes me happy.
With the .22 rifle, I was holding over at the top of the bottom crosshair post for .22 rounds at 200 yards and a 25-yard zero.
In all, the Rapid Range Reticle can be used effectively for holding over in whatever cartridge you’re using. It will take some figuring out what your holdovers are and will depend on what your patience and tolerance levels are to use it as such.
Tri-Color RGB Illumination
The Rhino 4x prism sight has triple illumination with red, green, and blue colors. Each LED has three brightness settings each. The Rhino’s illumination is powered by a CR2032 battery which I always have on hand given that many optics now use the CR2032 battery as a standard power source.
The floating BDC portion of the reticle is what’s illuminated, the crosshair posts are not. There is quite the light bleed when using the highest illumination setting and it distorts reticle clarity.
Unfortunately, with the blue illumination, I can’t see any of the holdovers. The reticle gets blurry. With green, it’s a little bit better but I get the best results with the red illumination. It’s crisp and sharp, less light bleeding and flaring, and I can actually read the 4 and 6 holdover numbers.
Given that you can be slightly off zero if you switch between colors and I can’t actually effectively use all of the color options (though blue is a nice change!), I will be strictly using the red illumination. With that opinion, I would like to see a single illumination sight with more brightness settings instead of the color variations with limited settings.
I will mention here that the battery that came with the Rhino R4X died during field testing. I also never left it on and used manual off throughout this time period. It was about a week in before I needed to replace to it. I’m wondering if it was a bad battery to begin with because I didn’t feel like the illumination was very bright especially in outdoor conditions.
With a new Energizer battery, the illumination is strong but still a bit hard to see in bright conditions. You don’t always need it though because the reticle is glass-etched and is black without illumination. This is a huge difference between prism sights and reflex sights.
If there’s an issue with runtime on the new battery, I’ll update. At this point, no news is good news.
Ozark Rhino Reflex RDS VS Rhino 4x R4X-RGB
The Rhino red/green reflex sight is very different to the Rhino 4x prism sight. They work differently but they still fall under the red dot sight category. The R4X sight is better for those with astigmatism and who want some magnification built into the sight.
The Rhino red/green reflex sight is excellent for a non-magnified sight picture for inside 100 yards. Though the R4X has a reticle to go out to 600 yards, I’d say it really only has a couple more hundred yards of effective use over the Rhino reflex sight just because of its small size which makes it hard to see.
When it comes to illumination, I prefer the dual colors and brightness of the Rhino reflex sight. The blue in the Rhino 4x prism sight is unusable to me in my opinion, so I’d rather less color options with more brightness settings which the Rhino reflex sight has.
Though the 3.5" of eye relief is good on the 4x magnified prism sight, the eye relief is unlimited on the Rhino reflex sight – thanks to its non-magnified design. Both are accurate, hold zero, and have solid mounts.
If it’s about money alone, the Rhino reflex sight is cheaper than the Rhino magnified prism sight.
The Rhino red/green reflex sight offers simplicity, ease of use, compactness, and above average performance for a budget red dot sight. However, if the illumination fails, you’re done for. You’re also limited if you’re after distance and precision.
The Rhino 4x magnified prism sight offers fixed magnification, a doable but small reticle, and integrated rails for attaching accessories. If the illumination fails, you still have a visible reticle to stay in the game, hunt, or keep at it at the range. However, you don’t want this sight to get wet or you’ll risk internal condensation and a blurry sight picture.
Ozark Rhino 4x32 VS Trijicon ACOG 4x32
The first thing I think of when someone says ACOG is fiber optics. There’s no fiber optics in the Ozark Rhino 4x. However, Trijicon does have an LED ACOG 4x32 sight. How does it compare?
Firstly, the Rhino 4x R4X-RGB does not cost over $1600. It definitely has that going for it over an ACOG. Secondly, the ACOG takes a AA battery while the Rhino takes a CR2032. If all things were equal, I’d take the CR2032 over a AA, but things aren’t equal. The LED ACOG will run for over 12,000 hours on setting 4. Both are continuous-on prism sights, but it’s clear that Trijicon takes the lead on battery runtime here.
In terms of size and weight, the Rhino comes in at exactly 6.5” long whereas the ACOG is 6” long. The Rhino is lighter at exactly 16 oz while the ACOG weighs 17.6 oz.
There’s a lot more that can be compared, but the fact is that the Rhino isn’t an ACOG. It also doesn’t cost like one, and the Rhino actually has better eye relief and 0.25 MOA adjustments too.
What it will come down to is, if you can afford to drop over $1000 on the LED ACOG 4x32 for duty use and real-world SHTF encounters, then go with the Trijicon. The Ozark Rhino 4x is a very budget alternative for average applications that the rest of us are doing.
Limitations of the Ozark Armament Rhino 4x
Not Waterproof
The Ozark R4X prism sight is water resistant. It can handle a light rain, but I would not recommend letting it get wet for more than that. Though the housing is all metal construction and very durable, the weak link in this sight is the ocular housing.
During water testing, the main body, including around the turret bases (no caps on!), held up extremely well. Unfortunately, water seeped in through the diopter and there are drops on the inside of the lens. This could be a deal breaker for cold weather like Winter hunts.
The saving grace so far has been that the drops dried up and I can’t see any spots looking through the glass.
As a side note, you don’t want to let water dry on the lenses, so don’t forget to use that included microfiber cloth to dry them off. Unfortunately, there’s nothing you can do if water gets in the inside – hopefully they’ll dry up and won’t blur the sight picture. I count myself lucky in this.
Popular Questions About the Ozark Armament Rhino 4x
The Ozark Rhino 4x red dot sight does not come with fiber optics. The R4X illumination is powered only by a battery source. Though the included one-page user manual sheet implies that it comes with fiber optic sights, it does not.
From what I’ve gathered, there may have been an option to get the R4X with fiber optic iron sights installed on the top of the sight. The front sight would be situated on the integrated rail and the rear sight over the ocular bell. This doesn’t seem to be the case anymore, and it certainly wasn’t the case with the one that was sent to me. I didn’t expect fiber optics, but the paper did confuse me.
The illumination control is a rotary knob located on the top of the sight. The illumination settings are indicated by color and number. The actual letter references, R, G, and B indicate the LED that will be activated for illumination. These letter references are the manual off settings.
The Rhino 4x R4X-RGB prism sight does not come with lens covers. It does come with a built-in mount, lens cloth, CR2032 battery, a specs sheet, and a warranty registration card reminder. The Rhino Red/Green Reflex RDS comes with flip-up lens caps.
The Ozark Armament Rhino 4x red dot sight is factory set for parallax at 100 yards. Focusing is great at 25 yards but I’d say you can come down to about 15-20 yards before you lose clarity. I did not notice any perceivable parallax issues between 25 to 200 yards.
The Rhino R4X-RGB is covered under a hassle-free lifetime guarantee called the No B.S. lifetime warranty. It covers defects and normal wear and tear. Registration is required within 15 days to ensure the Rhino 4x sight can be covered under the warranty.
Just to be clear, intentional user damage, like me deliberately pouring water over the sight, is not covered. It’s just common sense.
Ozark Rhino 4x: The Affordable ACOG?
In total, I love that the Ozark Armament Rhino 4x has great adjustments. They’re positive, crisp, and although they’re ‘backwards,’ they track accurately. The mount is sturdy and my Rhino 4x has held zero, and I highly recommend it for rimfire rifles and .223/5.56 mm AR-15 rifles.
Though I think more can be done to waterproof it around the ocular bell and the reticle could stand to be a bit bigger for better BDC visibility, the Rhino 4x works well for its price point.
If you’re into the whole tactical look, the integrated rails provide versatility for accessory attachments. I think it’s cool, and a couple extra pieces on the R4X doesn’t really add a whole ton of weight either.
Though the Rhino 4x ain’t no ACOG, it certainly has features that can be compared and justifiably compromised on for its low price. With this mindset, it’s fair to say it’s an affordable alternative to one!
Thank you to Ozark Armament for sending me the Rhino 4x R4X-RGB red dot sight to field test. Please note, even though this product was provided by the manufacturer, all my opinions expressed are my own and not in any way influenced by the manufacturer.
Further Reading
