4 Best Red Dot Sights For FNX 45 Tactical [Updated 2021]

fnx45 with holosun 507c pov

There are tons of handgun optics on the market today!

Do you know which ones are the best red dot for FNX 45 tactical? we have tested a handful of sights based on their durability, compatibility, reticle, battery life and cost.

Don't waste money on a poor optic that breaks, get the ones that are already proven to work!

Let's check them out:

Our Best Reflex Sights For FNX 45 Tactical

Trijicon RMR Type 2 (3.25 MOA) - Best Overall


Why this is the go-to optic - Trijicon RMR is the gold standard for micro pistol reflex sights. The RMR is the go-to for handgun, rifle, and shotgun usage, Still to this day.

Multi Color Options - Match your FNX45 Tac with either Black or FDE.

Improved Accuracy - Super clean and fine 3.25 MOA dot works for shooters with astigmatism with super clear dot clarity

Built For Handgun - The RMR Type 2 is specifically built to handle handgun slide G force. The new battery compartment grips the battery tighter to prevent loose contact

Slide Racking Assist - Racking the slide one handed effortlessly by pressing the optic against hard surfaces. This gives the shooter large surface area to operate the slide 

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Trijicon SRO (5 MOA) - Largest FOV

trijicon sro on fnx 45 tactical

Use FN RMR plate or CHPWS for direct mount

Why we picked this one - Effortlessly and instantly acquire the red dot in the center of the lens with that enlarged window frame. This means less time spend looking for the reticle or get lost in the window during follow up shots.

Since the FNX 45 Tactical has a 1911 style grip angle, the SRO makes sight picture acquisition way easier. You can also experiment with different size grip backstraps to slightly change the grip angle that's best for you.

Bigger Window  - Get on target fast, and reacquire the sight picture fast after follow-up shots. When you pick this up the first time you just wish you had it sooner.

Trijicon sro front glass

Easier Battery Access - Load/Replace battery right from the top! No sight removal or re-zero required

Better Follow Up - Increased sight acqusition speed including consistent fast follow-up shots without losing the dot inside the window.

Same RMR mounting footprint - Using the exact Trijicon RMR mounting footprint keeps everything compatible without having to buy special accessories.

See more Trijicon SRO pics & review

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Holosun HE507C X2 - Best Trijicon Alternative

holosun 507c x2 show reel

Use FN RMR plate or CHPWS for direct mount

Why people love Holosun 508T X2 - The Holosun HE507C X2 is by far the best Trijicon RMR alternative. The same durability & mounting footprint, and it's much cheaper.

Bigger Buttons - Enlarged adjustment buttons for better reach Upgraded from the previous model. 

Near Infinite Battery life - The Shake Awake technology & solar panel extends the battery life way past 50,000 hours. Motion sensor activates & deactivates the reticle for battery saving, and the Solar fail-safe power kicks in immediately when the battery dies, so the optic will always remain on.

holosun 507c x2 battery tray access 2

No Hassle Battery Swap - Access the CR1632 battery from the side tray to eliminate the need to remove the sight for battery swap and re-zeroing

At this price point, this optic almost surpasses the Trijicon RMR, and you'll save a ton of money. Just make sure to click the button below for the best deal.

Read HS507C X2 Review

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Leupold DeltaPoint Pro - Plate Or Mod Required

leupold deltapoint pro fnx 45 tactical

Use a spare M&P Core DDP mount plate)

leupold deltapoint pro plate part 171203

Torque specs included in the manual for a rock solid mount (FN doesn't provide DDP plate)

Why Use The DeltaPoint Pro - This sight is as top notch as much as a Trijicon SRO for the price. However, we ranked it last because it requires proper fitting or aftermarket optic to make it work.

Larger Window Than RMR - The first handgun optic in the market with a large window for faster target acquisition speed.

Extra Housing Protection - The added lens hood protects the optic from receiving direct impact that increases durability and making it fail proof.  

Easier Battery Access - Load/Replace battery right from the top! No sight removal or re-zero required. This user friendly design has been implemented into many other new optics today.

Read more DDP Review here

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Common FAQ

Red Dot Compatibility

The FNX 45 Tactical comes with sight mounting kit with plates and screws for the following sights:

Trijicon RMR & SRO, Holosun 507C and Docter Sight.

Aftermarket CHPWS plate is also compatible for a much tighter and rock solid mount.

Which Optic Plate Fits The Leupold DeltaPoint Pro? 

The Leupold DeltaPoint Pro can be mounted with Leupold Part #171203

The optic can be mounted directly to the slide without a plate, but requires some material trimming to fit the optic (NOT recommended)

Pick Optic Color: FDE or Black?

For aesthetic, it's all based on your preference.

3 & 6 MOA Size Selection For 45ACP

3 moa vs 6 moa dot sizes comparison

A 3 to 6 MOA dot size is great for the FNX 45 tactical at close range. 

6 MOA helps to get on target fast, and the 1 MOA fine dot is for shooting pistol long range.

Generally speaking the 6 MOA is much clear and crisp for shooters with astigmatism.

Learn more about 3 VS 6 MOA dot here

Optic Durability

Based on community feedback, the Trijicon RMR is the default go-to optic for FNX 45 Tactical, and the Holosun 507C is the second pick. 

A strong optic can survive recoil, and can be used as a slide racking device.


The Trijicon RMR is the go-to product for duty use, the Trijicon SRO for better fast dot acquisition and tracking.

The DeltaPoint Pro is a great optic, however, the plate goes on the slide with screw tension only so there will be some lateral shifts after 500 - 1000 rds.

For the price and durability without compromise, it will be the Holosun 507C!

Have fun on the range and be safe.

If you have any questions or would want to add anything to this content, please email badassoptic3@gmail.com

Tyler Brown

Tyler grew up in a firearm family, and now he runs his own firearm business in the Midwest. 4 years of experience managing an FN dealership with tons of firearm business & product knowledge