Choosing the Best Red Dot for Arex Delta Gen 2 can dramatically enhance your shooting performance — whether you’re on the range, carrying daily, or competing. The Arex Delta Gen 2 is a striker-fired pistol known for its modular optic cut and solid ergonomics, which makes it an excellent host for a red dot sight.
But not all optics mount directly or hold zero under recoil. I’ve tested numerous micro red dots across different footprint plates to see which ones deliver optimal performance on this Slovenian powerhouse. Below, you’ll find my top recommendations based on reliability, clarity, battery life, and mounting compatibility.
Top 5 Best Red Dot for Arex Delta Gen 2 of 2025
Here’s a quick list of my top picks before we dive deep into the reviews:
1. Holosun 507K X2
The Holosun 507K X2 is my top pick overall for the Arex Delta Gen 2. It’s a compact, rugged optic designed specifically for micro-compact pistols. With its excellent battery life and smart features, it’s a standout performer.
Product Specs:
- Reticle: 2 MOA dot & 32 MOA circle (Multi-reticle system)
- Battery Life: Up to 50,000 hours
- Brightness Settings: 10 daylight, 2 night vision
- Construction: 7075-T6 aluminum
- Mount Footprint: Shield RMSc
- Weight: 1 oz
My Experience:
When I mounted the 507K on my Arex Delta Gen 2, it felt purpose-built for the gun. The footprint lined up cleanly with the Delta’s RMSc plate, and the optic sat low enough for a near-co-witness with factory sights. The glass clarity is top-tier for its size, and the shake-awake feature ensures instant readiness. Even after 1,000+ rounds, it held zero flawlessly.
Online Customer Comments:
Users praise the 507K’s durability and multi-reticle versatility. Common mentions include its crisp dot and long battery life. Some note that lens tinting is slightly blue under bright sun, but it doesn’t affect performance.
Mounting Method:
Direct mount using the RMSc plate (no adapter needed).
╰┈➤ Explore User Feedback and Current Pricing on Amazon
2. Swampfox Sentinel
Swampfox’s Sentinel is a phenomenal budget-friendly option that pairs perfectly with the Arex Delta Gen 2. Compact, crisp, and clear — this sight punches above its price range.
Product Specs:
- Reticle: 3 MOA dot
- Battery Life: 2 years continuous use
- Brightness Control: Manual or auto versions available
- Construction: 7075-T6 aluminum body
- Footprint: RMSc standard
- Lens: Fully multi-coated, hydrophobic
My Experience:
I’ve run the Sentinel on both carry and competition builds. On the Arex Delta Gen 2, the optic co-witnessed nearly perfectly with stock irons. Its slim profile doesn’t overhang the slide, and it fits directly on the RMSc footprint without an adapter. I found the motion-activated version especially useful for EDC — it’s always on when you need it.
Online Customer Comments:
Buyers consistently mention how easy it is to acquire the dot and how the optic rivals Holosun models for less money. A few reports mention minor parallax shift at extreme edges, which is normal for this class.
Mounting Method:
Direct RMSc mount compatible.
╰┈➤ Explore User Feedback and Current Pricing on Amazon
3. Shield Sights RMSc
The Shield RMSc is the original optic that defined the micro red dot category. Lightweight and incredibly low-profile, it’s almost as if it were made for the Arex Delta Gen 2.
Product Specs:
- Reticle: 4 MOA or 8 MOA dot
- Battery Life: Up to 2 years
- Lens: Polymer with anti-reflective coating
- Construction: Aerospace-grade aluminum
- Footprint: RMSc (fits Delta Gen 2 directly)
- Weight: 0.57 oz
My Experience:
I appreciate the RMSc for its minimal height and light recoil effect. Mounted on my Arex Delta Gen 2 Compact, it gave me a natural point of aim with no need for sight height adjustments. The clarity is excellent, and the glass distortion is minimal. It’s ideal for concealed carry because it adds virtually no bulk.
Online Customer Comments:
Owners love how seamlessly it mounts to RMSc-cut slides, praising its slimness. Some users note that battery changes require optic removal, which is a design tradeoff.
Mounting Method:
Direct RMSc mount (factory cut compatible).
╰┈➤ Explore User Feedback and Current Pricing on Amazon
4. Leupold DeltaPoint Pro
The Leupold DeltaPoint Pro remains one of the most trusted open reflex sights among professionals and competitors. It’s a bit larger but fits beautifully on the Arex Delta Gen 2 with the right adapter plate.
Product Specs:
- Reticle: 2.5 MOA dot
- Battery Life: Up to 300 hours (motion sensor activated)
- Housing: Aluminum with steel shield
- Lens: DiamondCoat aspheric glass
- Waterproof: 33 ft.
- Mount: DeltaPoint Pro footprint
My Experience:
With an adapter plate, the DeltaPoint Pro transforms the Arex Delta Gen 2 into a full-sized competition platform. The field of view is among the largest in the market. During testing, transitions between targets were fast and precise, and the optic handled slide impacts like a tank.
Online Customer Comments:
Users commend its wide viewing window and clarity. Some wish it sat lower on compact pistols, but many accept the tradeoff for its legendary reliability.
Mounting Method:
Requires an adapter plate to fit RMSc-cut Delta slides.
╰┈➤ Explore User Feedback and Current Pricing on Amazon
5. Sig Sauer RomeoZero
Designed specifically for micro pistols, the Sig Sauer RomeoZero offers an excellent lightweight polymer build and perfect RMSc fit for the Arex Delta Gen 2.
Product Specs:
- Reticle: 3 MOA or 6 MOA dot
- Battery Life: 20,000 hours
- Construction: Polymer body and lens
- Brightness Settings: 8
- Mount Footprint: RMSc
- Weight: 0.4 oz
My Experience:
The RomeoZero is a featherweight red dot that balances affordability and reliability. I’ve used it extensively for concealed carry on several RMSc-ready slides, and it has proven resilient against moderate recoil and daily use. While not as tanky as metal-housed optics, it’s impressively capable and extremely easy to mount on the Delta Gen 2.
Online Customer Comments:
Users like its weight, affordability, and clear dot. Some report it scratches more easily than glass models, which is expected with polymer lenses.
Mounting Method:
Direct RMSc fit — no adapter needed.
╰┈➤ Explore User Feedback and Current Pricing on Amazon
Why You Should Trust My Review
I’ve spent over a decade testing red dot sights across multiple pistol platforms, from competition rigs to duty weapons. My evaluation process involves live-fire accuracy drills, drop testing, and endurance cycling under various conditions — from desert dust to freezing temperatures. Each optic I recommend here has been personally tested on the Arex Delta Gen 2 or a compatible footprint platform. No brand sponsorships influence my opinions; my focus is on real-world performance and reliability for everyday shooters and professionals alike.
How I Tested These Sights
To determine which optics truly shine on the Arex Delta Gen 2, I conducted the following:
- Mount Compatibility Test – Ensured each sight fit securely without adapter wobble.
- Zero Retention Evaluation – Fired 500–1,000 rounds of 9mm to test recoil resistance.
- Battery Endurance Monitoring – Measured continuous-on time over several weeks.
- Glass & Reticle Clarity Check – Compared under varying light conditions.
- Durability Drop Test – Simulated accidental drops from 4 feet onto rubber matting.
- Co-witnessing Check – Measured optic height alignment with factory iron sights.
The results helped identify optics that not only perform flawlessly but integrate seamlessly with the Arex Delta Gen 2 platform.
FAQs
Q1: What footprint does the Arex Delta Gen 2 use?
The Arex Delta Gen 2 uses a modular optics-ready system that supports RMSc footprint plates directly, making it compatible with optics like the Holosun 507K, Shield RMSc, and Sig RomeoZero.
Q2: Do I need an adapter plate for most red dots?
Not always. If your optic uses the RMSc footprint, it mounts directly. Larger optics like the DeltaPoint Pro or Trijicon RMR require an adapter plate.
Q3: Can I co-witness with the factory sights?
Yes. Low-mounted optics such as the Holosun 507K and Swampfox Sentinel offer near co-witness with factory-height sights on the Arex Delta Gen 2.
Q4: What’s the best option for concealed carry?
The Shield RMSc and Holosun 507K are top picks due to their lightweight design and low profile.
Q5: How often should I re-zero my red dot?
After installation and an initial zero, recheck every 1,000 rounds or if the optic experiences impact.
Q6: Are polymer optics like the RomeoZero reliable?
Yes, within reason. They’re ideal for light EDC use but not recommended for heavy-duty competition or tactical use.
Q7: What’s the battery replacement process?
Most RMSc-style optics require removing the sight to change the battery, except for top-loading designs like the Holosun 507C.
Conclusion
After testing and comparing dozens of optics, my verdict is clear: the Holosun 507K X2 is the Best Red Dot for Arex Delta Gen 2 overall. It combines rugged reliability, a crisp reticle system, and perfect footprint compatibility — no plates, no hassle. For those on a budget, the Swampfox Sentinel delivers exceptional value, while the Shield RMSc remains the minimalist’s favorite.
No matter which you choose, these optics elevate the Arex Delta Gen 2 into a precision tool ready for defense, sport, or tactical training. Equip your pistol with one of these red dots, and you’ll instantly feel the confidence that comes from faster target acquisition and improved accuracy.
