I bought a magnifier a while ago to pair with my Holosun HS510C. There is no better option to pair with it than the Holosun HM3X 3X magnifier.
During my ownership, I’ve figured out a few things I like and don’t like about it from its optics to its mounting system.
In my Holosun HM3X review, I specifically looked at value, the eye relief, quirks of the quick disconnect mount, and whether it works with back up iron sights too.
Read on for the details!
What I Like: Optical quality
What I Don’t Like: Adjustment tool
Best Uses: Hunting, Target Shooting, Competition, Old Eyes
- Magnification: 3x
- Objective Lens: 24mm
- Field of View: 7°
- Coatings: FMC
- Eye Relief: 2.75”
- Dimensions: 4 x 1.7 x 2.6”/ 9.5 oz
- Mount: Integrated QD mount
My Verdict: The Holosun HM3X is a high-performing magnifier that competes with similar alternatives at the same price point. It’s truly ambidextrous, has great optical performance, and the short, compact QD mount adds value to the entire package.
Why Trust Me?
After hundreds of hours of hand-testing magnifier in the field 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 target shooting, competition and hunting has been integral in putting together this Holosun HM3X 3X review.
Who is the Holosun HM3X Best Suited to?
Overall, the Holosun HM3X magnifier is well-suited to use with multiple types of red dot sights and provides 3x magnification. Listed at a competitive price point with alternative magnifiers, it offers a few features that sets it apart as an upgrade.
Those features include its excellent brightness and color fidelity, convenient quick detach locking mount, and the short mounting length that allows the body to hang over the charging handle and acquire full access to the eye box.
I would recommend it for some types of hunting, close to mid-range shooting, range use, perhaps some competition, and definitely for aging eyes.
How Does the Holosun HM3X 3X Perform?
In general, magnifiers have very short eye relief of around 2-3”. The Holosun HM3X magnifier eye relief is listed at 2.75” long according to the specs, and I’d say that’s about right – 2.75-3”. It feels a little more forgiving to be behind compared to the Sig Juliet 3 with 2.5” of eye relief.
I tested the HM3X with MBUS sights. First off, this pushed the Holosun HS510C onto the handguard. I suppose I could’ve moved it back one more rung, but it wouldn’t have made a difference.
As you can see, with the rear sight flipped down, it clears the height of the magnifier. When flipping the sight up, it catches at the diopter at two points. With a little encouragement (nudge) it pushes past the diopter to its fully engaged position.
This is definitely a doable setup for those who want to run back up irons. But of course, with minimal generous eye relief that comes with using a magnifier, you do end up in the nose-to-charging-handle position.
I like to back off with an adjustable stock at least one click. With the rear sight on the rail too, I get a tiny bit of vignetting. For actual shooting, I removed the rear sight and mounted the HM3X as far rearward as I could to have the body hanging over the charging handle instead of over the rear sight.
I’m extremely happy with the performance and quality of the Holosun HM3X magnifier. It does exactly what it’s supposed to – provide magnification, and it does it with great optical quality. The finish has already taken a hit in under a year, but the overall build quality is excellent.
Features & Benefits
The glass desired focus of the Holosun HM3X is very good. Resolution, contrast, and brightness are excellent. Color fidelity is superb as I didn’t notice any tints or color dropping in either the warm or cool extremes when used alone.
Since it does sit behind a red dot, it will show color aberrations from the coatings on the red dot sight. In this case, you can see the effects of the dichroic coating on the Holosun HS510C red dot - on the bluish side.
It has + and – 3 correction via the diopter, so it was easy enough to adjust for my eyes. The dioptric ring is very stiff, so no unintentional adjustments can be made. The ring itself feels like it’s made of metal but the ocular bell, I suspect, is actually made of plastic.
The HM3X provides 3x magnification, and it provides just the extra bit of power to see the target better. I could see .22 holes on cardboard at about 50 yards, so I’m very happy with the glass in the Holosun magnifier.
The field of view is 7° (37 feet/100 yards) and is very good for a magnifier. It’s on the wider end of the spectrum and about even with the EOTech G33, Vortex VMX-3T, and other popular red dot magnifiers.
I measured around 0.9-1” for the objective lens putting it at around 24mm.
Overall, the build quality is good. The Holosun 3x magnifier is made with durable aluminum housing and finished with a black micro-arc oxidation (MAO) finish. It’s supposed to be superior to a matte anodized finish, but the HM3X has taken on some wear-and-tear in less than a year of ownership.
I really like that it feels solid in the hand. It weighs 9.5 oz. It’s not a compact magnifier as it’s 4 x 1.7 x 2.6” in size. What I feel makes up for its length and size is the short and compact mount. It allows the majority of the magnifier to hang over the charging handle allowing for accessible eye relief and short mounting length.
It’s dust and waterproof rated with an IP67 rating. It’s been nitrogen-purged for internal protection against condensation and fogging. It can be submerged, not that you’d want to though, to a 1-meter depth for 30 minutes. The HM3X has also been shock rated for 1000G.
Quick Release Locking Mount
The HM3X magnifier comes with a quick disconnect mount, otherwise known as a quick release or quick detach mount. It’s the same kind of lever lock mount that came with the Holosun HS510C. Release the lever, attach the mount to the rail and apply pressure to close the lever and engage the lock.
It’s compact, simple, and easy to use. I haven’t experienced any wiggle or loose tension. The crossbolt will loosen or tighten tension if it needs some minor adjustments out of the box. The included T10 Torx tool will get it done.
The QD mount is awesome. I love it because it makes mounting and unmounting a breeze. You don’t need to remove the entire optic if you want 1x performance with the red dot sight. The Holosun HM3X 3X flip to the side.
What I find a lot of value in is the locking mechanism. It’s small, but it works. You hear an audible click when the lever has actively engaged the lock. It doesn’t move or wiggle out of place. I like that it’s not just tension you’re relying on but that there’s also a lock that secures its position on the rail.
Flip to Side Mount
I’ve always liked push button magnifiers because then I know it will not unintentionally flip when I don’t want it to. The Holosun magnifier lacks this push button, but I found that I didn’t miss the extra step at all. I just grabbed it and shoved it out of the way or nudge it when I want it engaged.
There is a tension screw on the rear of the mount to adjust tension if needed. Unfortunately, I did experience the magnifier flipping to the side when I tested for it. If I held my setup on the side and shook it up and down, the motion flipped the magnifier in and out of engagement.
It only did this when I would intentionally do this and has never happened under normal conditions at the range or during transportation. I should state that this only happened after I had messed with the mount screws. This did not occur out of the box.
Update: The fix to this was so easy, it hurts to admit it. Because I meddled with the base screws on the mount, it loosened the tension of the hinge. A little Loctite will be needed to make sure those screws don’t come loose again. A few dabs of this and the hinge is back to stiff operation and the HM3X does not unintentionally flip! I’m ecstatic with the fix!
Though the magnifier has a 4” length, the mount is only 1.75” (approx.) long. The mount requires four rails on a Picatinny rail for correct mounting. The lever could be described as small, but it fits the compact concept of the mount.
As is appropriate for magnifiers with limited eye relief, the mount attaches to the Holosun HM3X at its front under the objective lens bell. This ensures the length of the magnifier hangs over the charging handle.
Out of the box, the Holosun magnifier is setup for a 1.41” height that provides an absolute co-witness with irons. As a result, it fits perfectly to height with red dot sights on an absolute co-witness mount. A spacer is included in the box to acquire a lower 1/3 co-witness.
On those with a lower 1/3 mount, the height difference can be seen, but it didn’t negatively affect the sight picture all that much - not that I could tell.
For more on absolute co witness, check out our Co-Witness Sights Explained guide!
The Holosun can be installed for flip-to-side benefits for left-handed shooters or those who prefer it flipped to the left. Like push button magnifier mounts that end up backwards, the push button to release the QD locking lever will also be placed backwards (in the forward-facing position).
I will state that if you need to switch it to the left, only remove the screws that connect to the magnifier body. Do not mess with the screws connected to the mount base. You do not need to touch these screws in order to switch the swing position.
I did this and found that the hinge mechanism lost a little bit of tension and now flips to the side with less resistance than it had before. Unfortunately, the tension screw is bottomed out, so I can’t adjust for a tighter flip. (The fix for this was a little Loctite to prevent the screws from coming loose!)
Of course, it still has good resistance and tension and I’m not too disappointed with it, it’s just something to know before you decide to mess with things. A little Loctite might be needed for the screws when you reassemble.
As a side note, I've read a lot of complaints that the screws were difficult to remove. Though you can see a tiny amount of Loctite was used in installation, they were not hard to remove at all - at least for me.
Limitations of the Holosun HM3X
The tiny metal protrusion in the rear of the mount is an adjustment tool to center the reticle within the FOV of the magnifier. Though the concept is appreciated, I found a flathead screwdriver much more convenient to use.
The tool itself is tiny. Even with my normal sized fingers, I found it hard to grip when making adjustments. If you have bigger fingers, this tool proves useless.
Popular Questions About the Holosun HM3X
The Holosun HM3X magnifier comes with rubber bikini caps in the box. They are approximately 0.5” deep. The rubber caps fit the magnifier even when the diopter is fully extended.
Included rubber bikini cap covers - Image by Tina Fa'apoi (Own Work) for Target Tamers
In general, Holosun optics are made in China. The box confirms that the Holosun HM3X magnifier is indeed made in China.
Country of manufacture printed on the box - Image by Tina Fa'apoi (Own Work) for Target Tamers
On average, prism sights and magnifiers are not typically used together. A benefit of a prism sight is magnification. However, there are some 1x prism sights such as the Vortex Spitfire AR red dot. The HM3X magnifier can be used with a prism sight if positioned just right behind it.
The Holosun HM3X magnifier will work with multiple red dot sights of various make and model. Though the HM3X pairs excellently with the Holosun HS510C, it also works with the Primary Arms SLx MD-25, Vortex StrikeFire II, and more.
Requirements to consider include the same approximate height between the red dot and magnifier and enough rail space behind the red dot to mount the magnifier. It may mean moving the red dot further forward on the rail.
Tested with various red dots - Image by Tina Fa'apoi (Own Work) for Target Tamers
Overall, the HM3X magnifier is covered by Holosun’s Limited Lifetime Warranty that is valid only to the original purchaser. Though a repair or replacement will be provided by Holosun in the event the defect is covered, shipping costs are on the owner.
Good Value & Top Competitor: Holosun HM3X Magnifier
The Holosun HM3X magnifier offers the most value in its optical quality with extremely clear glass performance. The build is solid, and the mounting system is reliable out of the box. Versatility is offered with the included spacer, but tampering with the mounting system will impact hinge tension.
I’ll figure out a fix for this, but as it stands, it’s been a workhorse for me. I think its glass performance and eye relief is better than my other favorite, the Sig Sauer Juliet 3 Micro, but I think I still prefer the push button since I haven’t had tension issues with that.
I find the HM3X to be a solid performer and a top competitor among the best red dot magnifiers. I have no qualms recommending it with an understanding of the small quirks about it. It’s on par with magnifiers from other manufacturers as far as price is concerned, but I think its glass, QD locking mount, and ambidextrous benefits gives it an advantage over the rest.