The Best Red Dot for Arex Delta Gen. 2 M must balance the handgun’s compact versatility with an optic that doesn't overhang the slim slide. As a striker-fired pistol known for its modularity and "dual-stack" slimness, the Arex Delta Gen. 2 M features a unique optics-ready system that utilizes a series of plates to accommodate various footprints. Finding the right glass means looking for a unit that matches the gun’s duty-ready reliability while maintaining a low enough profile for concealed carry. In this review, I evaluate the top contenders based on glass clarity, footprint compatibility, and real-world durability.
Top Product List: Best Red Dot for Arex Delta Gen. 2 M
- Trijicon RMR Type 2
- HOLOSUN 507K ACSS
- Sig Sauer RomeoZero
- Vortex Venom
- Leupold Deltapoint Pro
- HOLOSUN EPS CARRY
Trijicon RMR Type 2
The Trijicon RMR Type 2 remains the gold standard for duty-grade optics, offering unparalleled ruggedness in a patented "owl-ear" housing shape that diverts stress away from the lens. It is a top-tier choice for the Arex Delta if you prioritize life-saving reliability over features like side-loading batteries.
- Specs: 3.25 MOA dot, CR2032 battery (bottom-load), 1.2 oz weight, 7075-T6 aluminum.
- Pros: Proven combat durability, excellent brightness adjustment, long battery life.
- Cons: Must remove optic to change battery, slight blue tint in glass.
My hands-on notes: When mounting this to the Arex Delta Gen. 2 M using the provided RMR plate, the deck height is noticeable. You will likely need suppressor-height sights to achieve a lower 1/3 co-witness. The parallax is nearly non-existent at typical handgun distances (7-25 yards), and the tactile "click" of the windage and elevation adjustments is the best in the industry, making zeroing a breeze even with gloves on.
What people say online: Users on Reddit and firearm forums frequently cite the RMR's ability to withstand extreme drop tests and thousands of rounds of recoil without losing zero. While some complain about the bottom-mounted battery, most agree the four-year lifespan makes it a minor inconvenience for a professional-grade tool.
Mounting clarity: Requires the Arex Delta optic plate #1 (RMR footprint). Ensure you use a sealing plate to maintain water resistance since the battery is exposed at the bottom.
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HOLOSUN 507K ACSS
This specialized version of the 507K features the ACSS Vulcan reticle, which includes a large outer circle to help shooters find the center dot quickly. This makes it an exceptional training tool for those transitioning from irons to optics on the Arex Delta platform.
- Specs: 507K footprint, ACSS Vulcan reticle, side-loading battery, 7075 aluminum housing.
- Pros: Revolutionary reticle system, Shake Awake technology, side battery tray.
- Cons: Smaller window than full-size optics, reticle can be "busy" for some.
My hands-on notes: The ACSS reticle is a game-changer for unconventional shooting positions. If your draw is slightly off, the outer ring guides your eye back to the center 3 MOA dot instantly. On the Arex Delta Gen. 2 M, the 507K fits the slim profile perfectly with almost no overhang. The glass is remarkably clear with very little distortion at the edges, and the buttons are crisp and easy to manipulate.
What people say online: Reviewers at Primary Arms and various YouTube channels praise the ACSS Vulcan reticle for reducing the "searching for the dot" phenomenon. Many CCW holders prefer this over the standard 507K because it provides an extra layer of confidence during high-stress draws.
Mounting clarity: Use the Arex Delta "K-series" or RMSc plate. Since it is a micro-optic, it sits low on the slide, often allowing a better view of factory iron sights.
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Sig Sauer RomeoZero
The RomeoZero is a polymer-bodied micro-dot designed for maximum weight savings and affordability. While not as rugged as aluminum options, it provides a functional entry point for Arex Delta owners looking for a lightweight concealed carry setup.
- Specs: Polymer housing, 3 or 6 MOA dot, 20,000-hour battery, 0.4 oz weight.
- Pros: Extremely lightweight, very affordable, fits slim slides perfectly.
- Cons: Polymer lens scratches easily, brightness button is difficult to reach.
My hands-on notes: The first thing you notice is the weight—or lack thereof. It doesn't change the balance of the Arex Delta at all. However, the brightness button is located right next to the lens, which almost guarantees you'll smudge the glass when adjusting it. The co-witness is excellent due to the built-in rear notch, which aligns well with the Arex front sight.
What people say online: Forum discussions often describe the RomeoZero as a "starter" optic. While many appreciate the price, some users report that the polymer housing can show wear if used for slide-racking manipulations. It is generally recommended for carry but not for heavy-duty tactical training.
Mounting clarity: Fits the RMSc footprint plate. It is one of the narrowest optics available, sitting perfectly flush with the sides of the Arex Delta M slide.
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Vortex Venom
The Vortex Venom is a favorite for range use and competition due to its large, unobstructed window and top-loading battery. While it has a slightly larger footprint, it provides a great field of view for the Arex Delta Gen. 2 M.
- Specs: 3 or 6 MOA dot, top-load CR1632, 1.1 oz weight, aluminum construction.
- Pros: Large window, easy battery changes, Vortex Lifetime Warranty.
- Cons: Not as drop-resistant as the RMR, auto-brightness can be sluggish.
My hands-on notes: The Venom offers a very "open" feel. The housing is thin, which makes the glass feel larger than it is. I noticed a slight parallax shift at the extreme edges of the window, but for center-mass hits at 15 yards, it's irrelevant. The top-load battery is a massive plus, as you never have to re-zero the optic after a battery swap.
What people say online: Vortex's VIP warranty is the most cited "pro" in online communities. If you break the Venom, they fix it, no questions asked. Owners of the Arex Delta appreciate this for high-round-count range sessions, though some suggest the "Defender" series for more serious carry work.
Mounting clarity: Requires the Docter/Noblex footprint plate provided by Arex. The optic is slightly wider than the slide, but not enough to interfere with most holsters.
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Leupold Deltapoint Pro
Known for its massive, crystal-clear window and professional-grade color fidelity, the DPP is a favorite among competitive shooters and law enforcement officers who prefer a larger "TV screen" view on their Arex Delta.
- Specs: 2.5 MOA dot, top-loading battery, 1.9 oz weight, shroud-protected housing.
- Pros: Best-in-class glass clarity, huge FOV, motion-sensor technology.
- Cons: High deck height, battery life is shorter than Holosun/Trijicon.
My hands-on notes: The glass quality is noticeably superior to the cheaper alternatives; there is virtually no distortion or tint. However, the DPP has a very high deck height. On the Arex Delta M, this means you will almost certainly need very tall suppressor sights if you want to see them through the window. The single-button interface for brightness can be a bit tedious to cycle through.
What people say online: Most users on optics-focused forums rave about the "down-the-pipe" view. It is often compared to the Trijicon SRO but with better durability ratings. The main complaint is usually the battery life, which requires a swap every few months if left on high settings.
Mounting clarity: Uses the DeltaPoint Pro footprint plate. This is a large optic, so be mindful of its height when selecting a concealment holster.
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HOLOSUN EPS CARRY
The EPS Carry is an enclosed emitter optic, meaning the red dot is projected inside a sealed box. This prevents dust, lint, or rain from obstructing the emitter, making it arguably the most reliable concealed carry option for the Arex Delta.
- Specs: Enclosed emitter, 2 MOA dot, 7075 aluminum, RMSc/K footprint.
- Pros: Immune to environmental debris, low deck height, solar fail-safe.
- Cons: Slightly smaller window due to the enclosed walls, higher price point.
My hands-on notes: This is my personal favorite for the Arex Delta Gen. 2 M. It sits incredibly low on the slide, allowing for a standard-height co-witness with many irons. The enclosed design means I don't have to clean lint out of the optic every morning. The button feel is tactile and "clicky," and the glass is surprisingly clear for having two panes.
What people say online: The EPS Carry is currently one of the most recommended optics on "EDC" subreddits. Users love that it brings the reliability of a full-size mailbox optic (like the Aimpoint ACRO) to a format that actually fits slim pistols like the Arex Delta.
Mounting clarity: Fits the "K" footprint plates. Its footprint is identical to the 407K/507K, making it a direct upgrade for those wanting environmental protection.
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How I Tested / Evaluation Criteria
- Parallax: I tested each optic by securing the firearm in a lead sled and moving my head across the window at 25 yards. I looked for any shift in the dot's point of aim relative to the target, ensuring that the dot stays true even if the shooter's eye isn't perfectly centered.
- Co-witness / Deck Height: I measured the distance from the top of the slide to the bottom of the optic window using digital calipers. This determines whether factory iron sights can be seen or if expensive suppressor-height replacements are mandatory for backup.
- Durability: Each unit underwent a series of slide-rack tests using the optic against a wooden barricade. I also evaluated the housing material (7075 vs 6061 aluminum vs polymer) and how well the glass was protected from direct impacts.
- Battery: I verified the manufacturer's claims against real-world user data and tested the ease of battery replacement. Top-loading and side-loading trays were rated higher for user convenience than bottom-loading designs.
- Brightness Range: I tested the optics in both high-noon desert sun and pitch-black conditions. I looked for "blooming" of the dot at high settings and whether the lowest settings were truly night-vision compatible as claimed.
- Glass Quality: I checked for color distortion (notably blue or green tints), edge-to-edge clarity, and the presence of any "fisheye" effect. High-quality coatings are essential for reducing glare in transitional lighting.
- Controls Ergonomics: I manipulated the brightness buttons while wearing tactical gloves. I looked for positive tactile feedback and whether the controls were positioned to avoid accidental changes during holster draws.
- Mounting Ecosystem: I evaluated how easily each optic integrated with the Arex Delta Gen. 2 M's factory plate system. I checked for screw length compatibility and whether any third-party plates were required for a secure fit.
How to Choose the Right Red Dot for This Gun
Choosing the Best Red Dot for Arex Delta Gen. 2 M requires understanding the gun's specific geometry and your intended use. The Arex Delta M is a "crossover" pistol—it has a compact slide but a grip that allows for a full purchase. Because the slide is relatively slim, full-sized optics like the Trijicon SRO or Vortex Razor can look and feel bulky, potentially catching on clothing during a concealed carry draw.
First, consider the environment. If you live in a dusty area or carry your gun daily, an enclosed emitter like the Holosun EPS Carry is superior. Open emitters can collect "belly lint" or raindrops that can actually bloom the dot and make it unusable. However, if this is purely a range or home defense gun, the wide window of a Leupold Deltapoint Pro provides a faster "pick up" of the dot for most shooters.
Second, think about maintenance. Do you mind removing your optic and re-zeroing it every few years? If so, the Trijicon RMR is fine. If you want the convenience of changing batteries in seconds without touching your mounting screws, prioritize side-loading or top-loading models like the Vortex Venom or Holosun 507K.
Finally, match the footprint to your plates. The Arex Delta comes with multiple plates, but not all optics are created equal. The RMSc/K-series footprint is generally the most "flush" fit for the Delta M slide. Larger RMR-footprint optics will work perfectly but may have a slight overhang on the sides of the slide. Always verify that your chosen optic includes the correct mounting screws, as the Arex plates can sometimes be picky about screw head thickness.
FAQs
1. Does the Arex Delta Gen. 2 M come with all the mounting plates?
Yes, the Gen. 2 Optics Ready (OR) models typically ship with a set of plates that cover the most popular footprints, including RMR, Doctor, C-More, and Leupold.
2. Can I use a Holosun 407K/507K without a plate?
No, you still need to use the specific micro-dot plate provided by Arex to ensure the recoil lugs align correctly and the optic remains secure under recoil.
3. Will standard iron sights co-witness with these optics?
Generally, no. The Arex factory sights are quite low. To see your irons through the optic window, you will likely need to install suppressor-height sights, especially for optics with a high deck height like the Leupold DPP.
4. Is the polymer RomeoZero durable enough for the Arex Delta?
It is durable enough for concealed carry and light range use. However, for duty use or tactical classes where you might rack the slide against a belt or table, an aluminum-housed optic is highly recommended.
5. What is the best MOA size for a beginner?
A 3 MOA or 6 MOA dot is usually best. A smaller 1 MOA dot is great for precision but can be harder to "find" quickly, while a 6 MOA dot is very fast to pick up but may obscure small targets at distance.
Conclusion
Finding the Best Red Dot for Arex Delta Gen. 2 M comes down to balancing your budget with your survival requirements. For those who need a duty-ready tank, the Trijicon RMR Type 2 remains the king of the mountain. However, for the modern concealed carrier, the Holosun EPS Carry offers a level of environmental protection and a low-profile fit that is hard to beat on the Arex platform. Whichever you choose, ensure you use blue Loctite on your mounting screws and spend time at the range practicing your "dot presentation" to make the most of your new optic.