5 Best Red Dot Sights for the FNX 45 Tactical Pistol

Chris G.

The FN FNX pistol has always been a favorite of mine. This semi-automatic, polymer-framed American-made pistol can be chambered with 9×19mm Parabellum, .40 S&W, and .45 ACP cartridges. It deserves a high-quality red dot.

Do you own an FNX 45? Trying to find the right red dot sight for your FNX 45 Tactical pistol may seem a bit overwhelming. No need to worry, I’ve done the hard work for you and come up with five excellent choices that could improve your aim and shooting speed.

Our Best Red Dots for the FNX 45 Tactical Pistol

a closeup of the Best Red Dots for FNX 45 Tactical Pistol

If you’re thinking about upgrading your FNX 45 Tactical Pistol with a red dot, I have a few excellent suggestions for you. Consider this as an FNX 45 Tactical review. 

The Trijicon RMR stands as my favorite due to its overall excellent performance. 

If you’re tight on the budget but still want an excellent red dot, I recommend the Holosun HS507C, which doesn’t skimp on features.

Shooting in extreme conditions? The Leupold DeltaPoint Pro is a reliable choice.

The Trijicon SRO is popular for its large window, which gives the shooter an almost unobstructed field of view. 

For an appealing mix of quality and affordability, the Vortex Venom is a great option.

1. Trijicon RMR: Best Overall

When it comes to sight options for the FNX 45 Tactical Pistol, the Trijicon RMR red dot sight stands out as an exceptional choice. This sight’s design is akin to the Trijicon ACOG, which is known for its durability.

The RMRs unique design of its housing deflects blows and impacts rather than absorbs them, augmenting its overall sturdiness. It’s also advertised to be waterproof to up to 66 feet although I don’t really plan to submerge my weapon to that depth. However, it’s reassuring to know that the RMR will continue to function optimally even in the heaviest rain.

I’m also a fan of its true-color, multi-coated lens that produces wide-band light transmission, filters unwanted glares, and does minimal color changes in my view. 

With 1 MOA per click adjustment, altering the windage and elevation is uncomplicated. The adjustment dials don’t require tools, but a coin or a long fingernail can help.

The RMR has a cool feature that adjusts the brightness of the reticle according to ambient lighting conditions. Thus, there’s no need for manual adjustments (although you can do so). The auto-brightness adjustment also helps conserve the battery.

These features make the RMR my go-to red dot on the field.

Technical Specifications

Weight: 1.2 oz. (34.02g)
Magnification: 1x
Reticle Pattern: 3.25 MOA Dot
Reticle Color: Red
Illumination Source: Solid-state LED
Power Source: 3V Lithium Battery
Battery Life: Over 4 years of continuous use
Adjustment: 1 MOA Per Click
Mount: RM33 Low Picatinny Rail Mount
Housing Material: Forged Aluminum
Finish: Matte Black

2. Holosun HS507C: Top Class Budget Alternative

Unless we are millionaires, we all know that money is hard to come by. But we still want the best! Thus, when it comes to red dot sights for the FNX 45 Tactical Pistol, the Holosun HS507C makes a notable impression for being a reasonably priced high-end optic. It’s a great alternative to the Trijicon RMR. 

This model is a favorite among many due to its sturdy build thanks to its 7075 T6 Aluminum housing. Similar to the RMR, this Holosun red dot has an IP67 submersible rating; essentially, it’s waterproof.

The HS507C is equipped with a multi-reticle system, providing the flexibility to switch between a 32 MOA ring, a 2 MOA red dot in the center, or a combination of both. This adaptability allows for precise aiming under diverse shooting scenarios.

Another plus for me is its extended battery life, which can last a whopping 50,000 hours—that’s around 5.7 years! The inclusion of a side tray for fuss-free battery replacement is a boon for users, especially when changing in the field.

The Holosun HS507C is also filled with cool innovations. Its Shake Awake technology, for example, activates the optic at its latest settings at the slightest movement. The Solar FailSafe solar panel uses the sun to power the optic, assuring you much-needed power as long as there’s daylight. It automatically adjusts the brightness of the LED reticle according to ambient lighting conditions. The auto brightness mode is a winner to me.

These features ensure that the Holosun HS507C is always ready for action and dependable, thus it’s one of my favorites.

Technical Specifications

Reticle: 2 MOA Dot and 32 MOA Circle
Light Wavelength: 650nm
Reticle Color: Red
Parallax Free: Yes
Unlimited Eye Relief: Yes
Magnification: 1x
Multi-Coatings: Yes
Power Source: Solar and Battery
Battery Type: CR1632
Battery Life: 50,000 hours
Brightness Setting: 10 Daylight and 2 Night-vision compatible
Window Size: 0.63×0.91 inches
Dimension: 1.78 x 1.15 x 1.15 inches
Weight: 1.5 oz.
Housing Material: 7075 T6 Aluminum
Surface Finish: Anodized
Adjustment per Click: 1 MOA
Wind and Elevation Travel Range: ±50 MOA
Submersion Rating: IP67
Vibration: 5000G

3. Leupold DeltaPoint Pro Reflex Sight: Best in Durability

Firearms are often subjected to vibrations, recoils, physical stress, and harsh conditions. We need accessories that can withstand this abuse.

Enter the Leupold DeltaPoint Pro reflex sight, which distinguishes itself as another premier red dot sight for the FNX 45 Tactical Pistol because of its excellent durability. This sight, built with the strength of aircraft-grade aluminum, is designed to withstand tough conditions and lots of abuse. It is fogproof, shockproof, and waterproof for up to 33 feet, making it ideal for high-stress situations. Yes, it’s built like a tank!

The optic can survive temperatures of -40 degrees Fahrenheit up to 160 degrees Fahrenheit. I haven’t tried subjecting the optic to these extreme temperatures yet, but I did try using these during heat waves in Texas and a couple of blizzards on a cross-country adventure to Canada. The DeltaPro Point worked without a hitch.

There’s another feature of the Leupold DeltaPoint Pro that makes it one of my favorites. It has a large, scratch-resistant window that provides an uninterrupted crystal-clear field of view with a pronounced 2.5 MOA dot reticle, ensuring easy target acquisition. A notable feature of this sight is Leupold’s Motion Sensor Technology, which turns off the illuminated reticle after five minutes of inactivity, thereby preserving battery life. The reticle itself has 8 adaptable brightness settings.

Changing the battery in the field is easy with a conveniently accessible battery compartment. 

The DeltaPoint Pro is built to withstand various weather conditions due to its waterproof, fogproof, and shockproof properties, making it a dependable piece of equipment under any circumstance. This is why the DeltaPoint Pro is among my preferred choice of optics.

Technical Specifications

Battery Type: CR2032
Daylight Bright Illumination: Yes
Magnification Type: Fixed
Reticle Focal Plane: Second Focal Plane
Reticle: 2.5 MOA Dot
Reticle Type: Illuminated
Switch Type: Push Button
Weight: 2 oz
Elevation and Windage Adjustment Type: Coin Click
Elevation/Windage Adjustment Value per Click: 1 MOA
Elevation/Windage Adjustment Range: 60 MOA
Elevation/Windage Adjustment Range: 17 MIL
Elevation/Adjustment Range: 175 cm at 100 meters
Elevation Per Revolution: 40 MOA
Windage Adjustment Per Revolution: 15 MOA
Magnification Min: 1
Eye Relief Low Mag: Unlimited
Battery Life, Low Intensity: 1600 hours
Battery Life, Medium Intensity: 1000 hours
Battery Life, High Intensity: 300 hours
Illumination Settings: 8

4. Trijicon SRO: Large Field of View

Having an encompassing field of view is important when it comes to competitive shooting or enforcing the law. That’s why for my FNX 45 Tactical Pistol, I use a Trijicon SRO red dot optic.

What I love about the Trijicon SRO is its extra-large, parallax-free window that easily allows me to see both my target and surroundings, vastly increasing my situational awareness. Despite the large window size, it’s low enough so that it can co-witness with my FNX’s iron sights. The Trijicon SRO can also be used in conjunction with  It’s my personal favorite for the FNX 45 Tactical Pistol, mainly because of how easy it makes target tracking – a key aspect in shooting competitions. 

The Trijicon SRO’s reticle is among the sharpest I’ve ever experienced. It has 8 brightness settings, including a “super bright” mode for exceptionally sunny days and 2 night vision modes. The sight has a “Lock Out” mode that secures the auto-brightness setting as well as a “Lock In” mode to secure manually set brightness adjustments.

Windage and elevation adjustments can be done without special tools. However, I find the dials difficult to turn without a coin.

The top-loading battery allows easy access to the battery compartment without having to remove the sight from the firearm.

Technical Specifications

Length x Width x Height: 2.2 in x 1.3 in x 1.4 in
Weight: 1.6 oz. (45.36g)
Magnification: 1x
Reticle Pattern: 2.5 MOA Dot
Reticle Color: Red
Illumination Source: LED
Illumination Settings: Automatic and 8 Adjustable Settings (2 NV, 6 Visible)
Power Source: 1 CR2032 Lithium Battery
Battery Life: Over 3 years of continuous use
Adjustment: 1 MOA Per Click
Adjustment Range: 150 MOA Total Travel
Mount: Not Included
Housing Material: 7075-T6 forged aluminum
Finish: Matte Black
Submersion Depth: 10 ft.

5. Vortex Venom: Best Value for Money

A great all-around red dot sight for the FNX 45 Tactical Pistol, the Vortex Venom stands out as a great choice for a red dot sight.

The fully multi-coated lenses and broad field of view enable swift target location and accurate shooting. I particularly like the large viewing window, which provides a near-perfect sight picture with no obstruction. Situational awareness is excellent.

Adapting to any light condition is a breeze with its 10 brightness settings and an auto-brightness mode managed by an ambient light sensor. The ArmorTek-protected lens is resistant to scratches, grime, and grease.

The tactile 1 MOA windage and elevation adjustments, along with the top load system for quick and effortless battery replacements, add to its practicality.

Its O-ring seals offer dependable performance, regardless of the environment. 

However, the battery life of the Vortex Venom is a drawback. At its brightest setting, it only runs 150 hours. At lower settings, the battery can power up to 3,000 hours. This is still way lower than some of the red dot sights in this list.

Vortex Optics Venom Red Dot Sight – 3 MOA Dot
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Technical Specifications

Reticle: 3 MOA Dot
Reticle Color: Red
Power Source: 1 x CR1632
Mounting: Picatinny / Weaver
Magnification: 1x
Impact Point Correction: 1 MOA
Windage Adjustment: 130 MOA
Elevation Adjustment: 100 MOA
Water Resistance: Waterproof
Dimensions: 1.9 x 1.1 x 1.0 inches
Weight: 1.6 oz.

Features to Consider When Choosing the Best Red Dot Sight for FNX 45 Tactical Pistols

As you select a red dot sight for your FNX 45 Tactical Pistol, pay attention to several vital features. 

  1. Mounting Compatibility: Check if the red dot sight is compatible with the mounting system of the FNX 45 Tactical. In general, avoid structural modifications to the pistol just to fit an optic; this can potentially affect your pistol’s performance. Use an adapter plate instead.
  2. Durability and Construction: Opt for a rugged and durable red dot sight. Look for sights with a robust construction, often made from high-quality materials such as aircraft-grade aluminum, to ensure longevity. Waterproof, fog-proof, scratch-resistant—these are some of the features that you want in a red dot.
  3. Reticle Type: Choose one that provides quick target acquisition and is easy to use in various shooting scenarios. Common reticle types include dot, circle-dot, and crosshair. 
  4. Adjustment Controls: Look for red dot sights with easy-to-use and accessible controls for brightness and windage/elevation adjustments. These controls should be user-friendly and should not require any special tool.
  5. Battery Life: A long battery life is an important factor. The longer the battery life, the better the sight is for extended shooting sessions or in critical situations. Check out models that offer automatic shut-off features or solar cells to conserve battery when not in use. These features help extended the battery life of the red dot.
  1. Lens Clarity and Coating: Go for a red dot sight with multi-coated lenses to enhance light transmission, reduce glare and reflections, and provide a crisp sight picture. I also suggest you choose optics with bigger windows for a much better sight window.
  2. Size and Weight: The FNX 45 Tactical is a sizable semi-automatic pistol. Choose a compact and lightweight sight that complements the pistol without adding excessive bulk to make it easier to handle and carry.

Maintaining Red Dot Sights for FNX 45 Tactical Pistol

Properly maintaining the red dot sight on your FNX 45 Tactical Pistol is key to ensuring its lasting functionality and reliable performance.

Regular cleaning of the lens is paramount. Using a lens cleaner and a soft microfiber cloth can effectively eliminate dust and fingerprints. Do not use abrasive cloths, materials, or chemicals that could potentially scratch the lens or remove its coating.

Battery maintenance is an additional consideration; always adhere to the manufacturer’s instructions for battery replacement and maintenance. Remove a dead battery promptly to prevent any leakage that could ruin your sight.

Routine inspection and tightening of mounting screws is another important aspect of maintenance, but caution is advised to avoid thread stripping from over-tightening.

Even though these sights are advertised as rugged and tough, do handle them carefully. Avoid nasty falls and impacts. Remember they are still electronic devices, and you don’t want to spend that much money only to have your sight damaged due to negligence.

“Maintenance is the key to longevity,” as the saying goes, and this is particularly true for red dot sights.


What is the best red dot for the FNX 45 Tactical handgun?  A good sight can improve your accuracy and speed up your target acquisition. It’s a matter of finding the right balance between features, durability, and cost that best suits your individual needs.

For me, the Trijicon RMR is a clear winner, followed by sights with large windows such as the Trijicon SRO or the Leupold DeltaPoint Pro. These have all the features I want.

Given the variety of excellent choices we’ve examined, choosing the right red dot sight for your FNX 45 will hopefully become easier. I’m sure you’ll find a sight that complements your style and improves your shooting skills.

About the author

The name's Chris. Just a regular dude who loves firearms. I've been shooting since I was a kid. My old man taught me the ropes.

I'll never forget the first time I missed an easy shot on a buck, thanks to a bum scope. The image was fuzzier than my dog's butt. After that, I got obsessed with understanding scopes. What makes the good ones tick and the bad ones trash. After a few years and a few thousand bucks, I learned what separates the winners from the losers. Once I had a good stockpile of knowledge, I launched this site.

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