6 Best Red Dot Sights For FNX 45 Tactical [Updated 2023]

Here are 6 best red dot sights for FNX 45 tactical. We have tested a handful of sights based on their durability, compatibility, reticle, battery life and cost.

Let's check them out:

Our Best Reflex Sights For FNX 45 Tactical

Disclosure: All products have affiliate links for earning commission to support the website when you purchase

Top 3 Options

Holosun HE507C X2 - Best Overall

fnx 45 tactical holosun 507c x2

The Holosun HE507C X2 is by far the best Trijicon RMR alternative. The same durability & RMR 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.

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


  • Much more affordable than Trijicon RMR
  • Uses RMR footprint
  • Long battery life + motion sensor aviation + solar power
  • No sight removal required for battery swap
  • Cons

    • Open emitter design attracts dirt
    • Solar power doesn't work indoor if ambient light is too weak
    trijicon rmr on fnx 45 tactical

    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 (Or try larger sizes)

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


    • Gold standard micro red dot
    • Duty grade quality
    • Long battery life
    • Multiple dot sizes to choose from


    • Bottom access battery compartment

    Trijicon SRO (5 MOA) - Largest FOV

    fnx 45 tactical trijicon sro

    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.

    The FNX 45 Tactical has a 1911 style grip angle, and the SRO makes sight picture acquisition & alignment 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 Trijicon SRO review


    • Very large FOV for dot tracking
    • No zeroing or sight removal required for battery swap
    • Same RMR footprint
    • 1 MOA, 2.5 MOA and 5 MOA
    • Lockout mode


    • A bit pricey
    • Not duty grade lens construction like the RMR

    Holosun 509T - Best Weatherproof

    FNX 45 tactical holosun 509T

    The Holosun 509T X2 features a fully enclosed body design to keep debris from entering the optic. This is a fully weatherproof optic for field use.

    Titanium Durability – Handles heavy recoil impulses and rough slide racking against hard surfaces. 

    32 MOA Reticle + 2 MOA dot - Same reticle system as 507C, But without the 32 MOA Only mode

    Battery Lasts A Long Time – 4+ years of long battery life + Solar Failsafe to keep the sighting system operational

    Clamp Mount - Tighter and much more secure mount (CHPWS adapter plate required)

    Motion Activated Reticle –  Shake Awake technology just like Holosun 507C

    Leupold DeltaPoint Pro - Plate Or Mod Required

    leupold deltapoint pro fnx 45 tactical

    Use a spare M&P Core DPP mount plate)

    leupold deltapoint pro plate part 171203

    See torque specs and how to install it here

    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 DPP Review here


    • As large as Trijicon SRO window
    • Additional lens hood protection
    • No sight removal required for battery swap


    • Single button to cycle through brightness adjustment
    • Requires mods or additional plates to install

    Swampfox Justice - Unique FOV

    swampfox justice red dot sight fnx 45 tactical

    The Swampfox Justice features a tapered field of view and it also uses the Trijicon RMR footprint.

    The body is made out of 7075 T6 aluminum, and it features a top load battery access just like Trijicon SRO.

    Overall, this optic is very affordable to get started with your FNX 45 Tactical.


    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