The FN 509 is a highly respected, optics-ready handgun trusted by military, law enforcement, and civilian shooters alike. Whether you own the FN 509 Tactical, Midsize, or MRD, adding the Best Holosun Red Dot for FN 509 can dramatically enhance your speed, accuracy, and confidence, especially in defensive or competitive shooting scenarios.
Holosun optics are known for their durability, innovative features like Shake Awake, Solar Failsafe, and multi-reticle systems, all while offering exceptional value. But with so many models like the 507C, 509T, 508T, or EPS Carry, how do you know which one fits your FN 509 best?
This guide breaks down the top 8 Holosun red dot sights compatible with the FN 509, including their specs, pros, cons, and mounting considerations. Whether you need a duty-ready closed emitter or a lightweight open emitter for everyday carry, we’ll help you choose the right optic for your setup.
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| 1)Holosun HS507C‑X2 (ACSS/Vulcan or dot + ring) |  |
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| 2) Holosun HS507C |  |
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| 3) Holosun HS507 Compact (507 Comp) |  |
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| 4) Holosun HS508T |  |
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| 5) Holosun HE509T (509T) |  |
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| 6) Holosun HS407C |  |
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| 7) Holosun 407K (K-series) |  |
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| 8) Holosun EPS / EPS Carry (RMR style) |  |
Quick Comparison
| Model | Footprint | Enclosed Emitter | Reticle Options | Battery Features | Notes |
| HS507C‑X2 | RMR | No | Dot, circle, ACSS Vulcan | Solar failsafe, Shake‑Awake | Top pick for FN 509 users
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| HS507C | RMR | No | Dot + circle (multi‑reticle) | Solar + Shake‑Awake | Best value open‑emitter setup |
| HS507 Comp | RMR | No | Very large window, CRS reticles | Shake‑Awake, manual brightness | For competition or maximum FOV |
| HS508T | RMR | No (open) | Dot only or Vulcan | Battery side load, solar supported | Titanium for rugged carry use
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| HE509T (509T) | 509T footprint | Yes | Dot, circle, or combo | Solar + Shake‑Awake | Most durable, duty-grade pick |
| HS407C | RMR | No | 6 MOA dot | Shake‑Awake, solar-supported | Compact, budget-friendly |
| HS507K / 407K | K-series | Enclosed small | Dot or ring/dot | Solar + Shake‑Awake | Flush install with K‑series plate |
| EPS / EPS Carry | RMR-compatible | Yes | Ring/dot or dot only | Shake‑Awake | Closed emitter with aftermarket plate |
Closed vs. Open Emitter: What Works Best on the FN 509?
When choosing a red dot optic for your FN 509, one of the biggest decisions is between a closed emitter and an open emitter sight. Both have their strengths, and the best choice depends on your environment, use case (duty, concealed carry, range, etc.), and personal preference.
Open Emitter Red Dots (e.g., Holosun 507C, 508T, 407C)
Open emitter sights are the most common type. They expose the emitter at the rear of the optic.
Pros:
- Lightweight and compact
- Typically offer a wider field of view
- Easy to clean the lens
- Generally more affordable
- Compatible with a wide range of mounting plates (especially RMR pattern)
Cons:
- Vulnerable to dirt, water, or debris blocking the emitter
- Performance can degrade in rainy or dusty environments
Closed Emitter Red Dots (e.g., Holosun 509T, EPS, EPS Carry)
Closed emitter optics are sealed, meaning both the front and rear glass protect the emitter from the elementsmuch like a rifle optic.
Pros:
- Weatherproof better in rain, snow, or dusty/muddy conditions
- Less likely to fail due to dirt or water on the lens
- Typically more rugged and duty-ready
Cons:
- Slightly heavier and bulkier
- Often require adapter plates for the FN 509
- Usually more expensive
Holosun Red Dot for FN 509
1)Holosun HS507C‑X2 (ACSS/Vulcan or dot + ring)
The Holosun HS507C-X2 is a new generation red dot optimised to allow faster target acquisition and greater accuracy, particularly when under stress, but it also works brilliantly in conventional circumstances.
It is created in conjunction with Advanced Combat Scopes Systems (ACSS), which designed the Vulcan reticle and was particularly meant to help speed the acquisition of targets and increase one’s accuracy in conditions of stress. Its RMR footprint also qualifies it as a first-rate option among users of FN 509 since it fits the factory optics-ready accessory system of the pistol.
Has an ACSS Vulcan reticle: a large center 10 MOA chevron with a huge outer 250 MOA circle. Only exposed when the optic is off-center, the outer ring provides the shooter with guidance back to target in the event of recoil or rapid target shift. This gives it special value to the novice red dot user or someone shooting under pressure.
Made of 7075-T6 aluminum, which makes it a lightweight but tough optic. It has Shake Awake, is solar failsafe, and has a side-mount CR1632 battery, which has a life of up to 50,000 hours. The brightness can be changed in 10 daylight and 2 night vision settings.
Key Specs
- Reticle: 10 MOA chevron + 250 MOA circle (ACSS Vulcan)
- Footprint: RMR (compatible with FN 509 plates)
- Battery: CR1632 (side-mounted), ~50,000 hours
- Brightness: 10 daylight, 2 NV settings
- Construction: 7075-T6 aluminum, IP67 waterproof
- Weight: ~1.5 oz
- Features: Shake Awake, Solar Failsafe, MRS
Pros
- ACSS Vulcan reticle improves speed and accuracy
- Massive outer ring helps center the dot quickly
- Long battery life with solar backup
- Shake Awake for instant readiness
- Durable, water-resistant housing
- Side battery tray = easy replacement
Cons
- Outer circle can feel distracting at first
2) Holosun HS507C
Holosun HS507C V2 is a durable, reliable, and well-built red dot sight that has gained its reputation among handgun lovers absolutely including FN 509 handgun owners.
It has the popular Trijicon RMR footprint, which makes it compatible with most of the avenues of optics-ready FN 509 types by either factory or aftermarket adapter plates.
This optic is of 7075-T6 aluminum housing that provides great shock and durability protection. It has the Holosun Multi-Reticle System (MRS). The shooter can alternate between a 2 MOA dot and a 32 MOA ring or the combination, depending on the flexibility of the precision aiming or quick target acquisition situations.
HS507C V2 uses a CR1632 battery of which has up to 50000 hours of usage. The solar failsafe keeps the optic working in bright lighting environments even when the battery runs flat. Its Shake Awake capability will automatically switch the sight on when you move and off in between so as to save battery life and keep your optic ready.
The V2 is rather functional, even though it is a bit older than the X2 model and the buttons on this model are large, and the glass is clear. It is one of the best alternatives to the FN 509 users seeking a proven, no-nonsense, modern platform red dot.
Key Specs
- Reticle: 2 MOA dot, 32 MOA ring, or both (MRS)
- Footprint: RMR
- Battery: CR1632, up to 50,000 hours
- Brightness: 10 daylight, 2 night vision
- Housing: 7075-T6 aluminum
- Waterproof Rating: IP67
- Weight: ~1.5 oz
- Features: Solar Failsafe, Shake Awake
Pros
- Proven reliability and durability
- Flexible reticle options for various uses
- Excellent battery life and solar backup
- Shake Awake for instant activation
- Works with FN 509 factory RMR plates
Cons
- Slightly bulkier buttons than X2 model
3) Holosun HS507 Compact (507 Comp)
Holosun HS507 Comp is conceived to be used in competitive and high-speed shooting, having one of the largest windows of the Holosun family.
Its broad field of view and blazing fast reticle settings make it an excellent selection for FN 509 owners who desire an optic that can make quick target transitions and fast first hit.
Although the sight-glass window is large and rectangular, a major step to better sight picture and minimizing the parallax error, it is incorrect to call this a 507 Comp.
This is good in USPSA, 1DPA, and self-defence shooting. The optic maintains Holosun’s dependable Multi-Reticle System (MRS), having 2 MOA, 8 MOA, 20 MOA, and 32 MOA reticles separately or collectively.
It is mounted in the Trijicon RMR footprint, and so the FN 509 can use factory or aftermarket RMR plates. Similar to all other high-end Holosun optics, this one is powered by a side-loading CR1632 battery (up to 50,000 hours), has Shake Awake, and 10 daylight + 2 NV brightness settings.
Offers the ultimate performance on the FN 509 with quick sight acquisition, unmatched confidence in situational awareness, and at the same time does not compromise durability.
Key Specs
- Reticle Options: 2, 8, 20, 32 MOA (single or multi)
- Footprint: RMR
- Battery: CR1632 (side-mounted), ~50,000 hours
- Brightness: 10 daylight, 2 night vision
- Construction: 7075-T6 aluminum
- Window Size: Extra-large rectangular lens
- Weight: ~1.7 oz
- Waterproof Rating: IP67
Pros
- Massive viewing window for faster target acquisition
- Multiple dot sizes for personalized aiming
- Shake Awake + side battery access
- Rugged and water-resistant build
- Perfect for competition or tactical use
Cons
- Slightly larger profile may not suit concealed carry
4) Holosun HS508T
The Holosun HS508T is a flagship open emitter red dot that has been developed to meet high standards of durability with value-added functionality.
It is one of the best options that can be used by FN 509 users who require a quality optic sight for duty, tactical, or defensive use. An RMR with Trijicon footprint fits the FN 509 readily with an optics-ready slide by using the factory or aftermarket RMR adapter plate.
Not an exaggeration, but the titanium construction of this 508T will perform better than any other optic in harsh conditions or as a daily carry. Multi-Reticle System (MRS) lets the user switch between a 2 MOA dot, 32 MOA circle, or the combination of 32 MOA circle and 2 MOA dot to increase speed in gaining the target and accuracy.
Optic has Shake Awake technology, solar safe, and up to 50,000 hours of runtime side-loading CR1632 battery. It also has IP67 waterproof, 12 brightness levels, 2 of them devoted to night vision, and the glass is very clear.
Key Specs
- Reticle: 2 MOA dot, 32 MOA ring, or both (MRS)
- Footprint: RMR (fits FN 509 with plate)
- Battery: CR1632 (side-mounted), up to 50,000 hours
- Brightness: 10 daylight, 2 night vision
- Housing: Titanium
- Waterproof Rating: IP67
- Weight: ~1.6 oz
- Lens: Clear, multi-coated
Pros
- Titanium body is extremely rugged and corrosion resistant
- Multiple reticle choices for speed or precision
- Long battery life with solar backup
- Shake Awake feature
- Easy battery replacement via side tray
Cons
- Slightly more expensive than 507C
5) Holosun HE509T (509T)
The Holosun HE509T is a rugged, fully enclosed red dot sight that provides high levels of reliability with intensive climate extremes.
It is one of the most long-lasting and combat-ready optics Holosun can give- perfect to use by individuals who use FN 509 in police, military, or self-defense situations.
Has a fully sealed emitter, compared with the open-emitter types, so the lens and internal components are less susceptible to water, mud, and debris.
Made of titanium, the optic is very tough but light. It comes with the Holosun Multi-Reticle System (MRS), which consists of a 2 MOA dot, 32 MOA circle, or both, saving the shooter different options between precision shooting and quick target acquisition.
This feature extends the brilliant lifespan of the CR1632 battery up to 50,000 hours because the Shake AwakeTM technology automatically turns on the optic when motion is detected and turns it off when stationary.
Since the 509T sports a proprietary mounting kit, FN 509 shooters will have to invest in an adapter plate, like the ones offered by C&H Precision or those offered by Apex Tactical, in order to have it installed on their guns. It has the rock-solid zero retention of screwed mount and better lens protection than open emitters once mounted.
Key Specs
- Reticle: 2 MOA dot, 32 MOA ring, or both (MRS)
- Footprint: Proprietary (adapter plate required for FN 509)
- Battery: CR1632 (side tray), up to 50,000 hours
- Brightness: 10 daylight, 2 night vision
- Housing: Titanium, fully enclosed
- Waterproof Rating: IP67
- Weight: ~1.7 oz
- Window Size: 0.66″ x 0.9″
Pros
- Fully enclosed emitter = top-tier durability
- Titanium housing resists drops, shock, and weather
- Multi-reticle versatility
- Long battery life + solar failsafe
- Shake Awake + side battery access
Cons
- Requires special adapter plate for FN 509
6) Holosun HS407C
HS407C is a durable and affordable red dot sight intended to serve the needs of shooters who want to have a simple optic without compromising durability and efficiency.
The Trijicon RMR footprint makes it a perfect match on the FN 509 pistol, either in the factory optics-ready mounting system or an aftermarket RMR plate.
It’s 407C also includes a crisp 6 MOA red dot, which is perfect when a quick target acquisition needs to take place, whether it be at a range, competing, or as a defensive mechanism.
Although it does not have the Multi-Reticle System (a feature that is in the 507C), the simple single-dot Reticle can be easier for some people to This is because some users prefer speed and clarity over being multifunctional.
It is IP67 waterproof and therefore impervious to rain and moderate submersion with the optic securely mounted within solid 7075-T6 aluminum.
The Holosun HS407C is a simple, lightweight, rugged red dot with no unnecessary bonuses that FN 509 users would turn to to view as a cost-effective product.
Key Specs
- Reticle: 6 MOA red dot (single reticle only)
- Footprint: RMR (fits FN 509 with RMR plate)
- Battery: CR1632 (side-loading), up to 50,000 hours
- Brightness: 10 daylight, 2 night vision
- Housing: 7075-T6 aluminum
- Waterproof Rating: IP67
- Weight: ~1.5 oz
- Lens: Clear, multi-coated glass
Pros
- Affordable and high-quality
- Large, fast-to-see 6 MOA dot
- Durable aluminum housing
- Shake Awake + Solar Failsafe
- Long battery life
Cons
- No multi-reticle system
7) Holosun 407K (K-series)
The Holosun 407K is a compact red dot sight that has been traditionally designed to fit onto thin pocket pistols, but can even be (with the correct adapter plate) mounted onto full-size guns such as the FN 509.
These are very low-profile and lightweight designs, which make them a good choice for concealed carry options or minimum optic configurations by shooters.
They have Shake Awake, 50,000-hour battery life, and side-loading battery (CR1632 which does not require a battery change to remove the optic.
407K has clear glasses, innovative lightweight design, and competitively priced that make them excellent options when you need to switch to a smaller optic that fits well with FN 509.
Key Specs
- Reticle (407K): 6 MOA dot only
- Footprint: Holosun K-series (adapter required for FN 509)
- Battery: CR1632 (side-loaded), up to 50,000 hours
- Housing: 7075-T6 aluminum
- Brightness: 10 daylight, 2 NV
- Waterproof Rating: IP67
- Weight: ~1 oz
Pros
- Compact and lightweight
- Side battery tray for easy replacement
- Great for concealed carry or slim slide profiles
- Shake Awake + long battery life
- Affordable price
Cons
- Requires adapter plate for FN 509
8) Holosun EPS / EPS Carry (RMR style)
The Holosun brand Holosun EPS (Enclosed Pistol Sight) and the EPS Carry are closed-emitter red dot optics meant to give old-school reliability and improved dimensions to single-stack type handguns such as the FN 509.
Its ultrahigh performance in all environments and the side-mounted battery were fine when they were invented on concealed-carry pistols, but these optics are fast gaining popularity on full-size guns as well, with their fully recessed emitter and overall rock-solid environmental design.
Has a bit larger window and is more adapted to full-size pistols (such as the FN 509), whereas the EPS Carry is adapted to slim-frame or subcompact pistols.
They have a Holosun K footprint, which does demand an adapter plate to be mounted upon the slide of FN 509. Nevertheless, quite a number of users find these optics to be better than the use of open emitters since, due to their fully closed nature, they are more resistant to rain, mud, and even when it is dusty.
The side-loading CR1620 battery provides 50,000-hour run time, and its optics include Shake Awake, Solar Failsafe, and IPX8 waterproofing iteration, which is the maximum possible in Holosun’s offerings on the pistol market.
Key Specs
- Reticle Options: 2 MOA dot or dot + 32 MOA ring
- Footprint: Holosun “K” (requires adapter for FN 509)
- Battery: CR1620 (side-mounted), up to 50,000 hours
- Construction: 7075-T6 aluminum
- Waterproof: IPX8 (submersible)
- Weight: ~1.4 oz (EPS), ~1.2 oz (EPS Carry)
- Brightness: 10 Waterproof
Pros
- Fully enclosed emitter protects against weather/debris
- Extremely compact and rugged
- Long battery life + Shake Awake
- Side battery access
- High waterproof rating (IPX8)
Cons
- Requires adapter plate for FN 509
Factors to Consider When Choosing The Best Holosun Red Dot for FN 509
When selecting the best Holosun red dot to suit your FN 509, there are some essential considerations the system has to deal with that determine product functionality, compatibility, and application. These are the most crucial aspects, and take them into account when make the most informed decision.
- Compatible Mounting (Footprint and Adapter Plates)
- FN 509 Tactical models usually take RMR footprints directly.
- The K-Series and EPS models will use adapter plates, usually made by C\&H Precision or CHPWS.
- Reticle Type and Size
Reticle Type and Size. The reticle used (which can be a full or broken circle) and its size are the next factors to consider.
- Holosun uses a Multi-Reticle System (MRS) to change to one of two reticles – either a 2 MOA dot or 32 MOA ring (e.g. 507C X2), or both.
- The less complex ones, such as the 407C or 407K, provide one dot (2 or 6 MOA).
- Power Features/Battery Life features
The battery of most Holosun optics has a maximum of 50,000 hours of battery life.
Those models that feature Solar Failsafe (such as the 507C, 509T, 508T) are backed up.
A special feature called Shake Awake sees that the sight switches on immediately as it detects movement.
- Strength & Building Structure
Titanium bodies (e.g., 508T, 509T) provide maximum durability-type use.
The 7075-T6 aluminum (e.g., 507C, EPS) has outstanding strength with reduced weight.
- Window Size and Sight Picture
Bigger windows (such as the 507C or 508T) provide a more enhanced field of view to allow faster target acquisition.
Smaller optics (such as the 407K, EPS Carry) are more suitable for concealed carry or models with slim profiles.
FAQs
- Which Holosun red dots are compatible with the FN 509 Tactical?
The FN 509 Tactical comes optics-ready and supports the RMR footprint. Holosun models like the 507C X2, 508T, and 509T fit directly or with a compatible plate. For smaller optics like the 507K, 407K, or EPS Carry, you’ll need a mounting adapter.
- Do I need an adapter plate for a Holosun optic on my FN 509?
Yes, unless your Holosun uses the RMR footprint (e.g., 507C, 508T, 509T), you will need an adapter. Models like the EPS, EPS Carry, and K-series use the “K” footprint and require an adapter plate from brands like CHPWS.
- Which Holosun red dot is best for concealed carry with the FN 509?
The Holosun EPS Carry or 507K are ideal for compact and concealed setups due to their small size, enclosed emitters (EPS Carry), and lightweight design.
- Are Holosun red dots waterproof and durable?
Yes. Most Holosun optics are rated IP67 to IPX8, offering protection against dust, rain, and even full submersion. Models like the 509T and 508T are built with titanium for enhanced durability.
Final Thoughts
Choosing the right Holosun red dot for your FN 509 depends on your specific needs, whether that’s concealed carry, range shooting, home defense, or duty use.
Open emitter models like the 507C X2 and 508T offer excellent visibility and fast target acquisition, while enclosed emitters like the 509T and EPS Carry shine in harsh environments where reliability is critical.
Key features like battery life, reticle style, footprint compatibility, and housing durability should all factor into your decision.
With the right mounting plate, nearly every Holosun optic can be fitted to the FN 509 platform. Holosun continues to offer reliable, feature-packed optics at a fraction of the cost of premium brands without sacrificing performance.
By understanding your personal use case and pairing it with the right Holosun model, you’ll get the most out of your FN 509 setup. Ready to upgrade your aim?
Check the links above for the latest deals and availability.
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