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  • Post last modified:September 8, 2023

In this Holosun 509T review, let's check out its specs, reticle, battery life, how it mounts, and see if it's worth buying after the first 300 rounds.

Let's check it out.

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Holosun 509T RD - Core Specs

509t on pdp
  • Magnification - 1X
  • Reticle - 2 MOA + 32 MOA Ring
  • Adjustment - 0.5 MOA / Click
  • Brightness - 10 DL&2 NV (Features Lockout Mode)
  • Construction - Solid titanium body
  • Submersion - IP67
  • Window Size - 0.63" X 0.91"
  • Body Dimension - 1.13" X 1.6" X 1.16"
  • Weight - 1.72 oz
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holosun 509t unboxing

You get:

  • Holosun 509T
  • Manual
  • Additional RMR plate adapter
  • Cleaning cloth
  • 1 CR1632 battery
  • Allen key
holosun 509t included items

First Impression

509t on pdp slide
509t side view

Right out of the box, it looks and feel very solid, and the window size is much bigger than the Aimpoint ACRO.

The front lens is positioned further back relative to the front lens to divert impact stress away to greatly increase durability.

It's a fully enclosed micro red dot sight for full size handguns.

When To Use This Optic

The Holosun 509T's closed emitter design makes it perfect for conceal carry and outdoor use under any weather and environment conditions.

Users can mount this on handgun slides, offset mounts and also use it as an primary optic. As it gets popular, more mounting options are made available to buy.

When it comes to closed vs open emitter red dot sights, a closed emitter design is what users want in rainy, muddy and sandy conditions.

Core Features

Window Size

The window size is: 0.63" X 0.91"

holosun 509t on walther pdp
Holosun 509t iso view

Here is the deal: The 509T is much affordable and the field of view is way bigger than the Aimpoint ACRO. 

For anyone looking for their 1st closed emitter pistol red dot sights, the 509T is a way better option. But before you make a purchase, let's check it out more:

Multi-Reticle System 

The Holosun 509T features the same multi reticle system just like the Holosun 507C X2, but without the 32 MOA Only mode

  • 2 MOA center dot only
  • 2 MOA + 32 MOA ring

The sight is very fast to pick up especially on a 1911 style grip angle pistols with tall sights that can help the shooter guide the eye to the dot.

holosun 509t pov 32 moa ring reticle

32 MOA represents approximately 32" at 100 yards, and it's big to acquire even if the reticle is completely slightly off center, the shooter can still see part of the ring as a reference to re-adjust to center the optic. 

However, the 32 MOA ring size looks very different based on your eye distance to the optic. When aiming with two hands extended all the way forward, the 32 MOA reticle felt like 50 MOA to the eye, but it's not a huge problem. 

2 MOA is a clean dot for anyone shooting long distance without all the clutter in the window.

For the most part, if you can't find the dot, it's not the optic. There are some tips to follow to help the shooter find the dot much faster and smoother.

  • The pistol's grip angle helps a lot 
  • Use tall co-witness sight to help guide the eye to alignment (Very subtle)

If you still can't find the dot, we got couple unobvious tips you can check out to help you find the dot on pistol easier.

Side Battery Access

holosun 509t battery access door

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The battery compartment can be accessed from the side in an small tray (Use provided allen key to open).

It takes a CR1632 battery to power the sight, and it lasts about 50,000 hours.

Common problems people report from other Holosun optics - Reticle blinking.

If the reticle blink, then it's time to replace the battery, reinsert the battery tray, or check the battery voltage to see if it's below 2.2Vdc.

holosun 509t solar panel top

In addition, the solar panel on the top immediate kicks in like a fiber optic absorbing any light source to keep the sight working.

It's plenty of battery juice to last you almost 4 years before consider changing it, but we highly recommend you to replace the battery every year just to top it off.

holosun 509t battery access

However, pulling the battery tray requires a thin flat head, and this is dreadful if you don't have a tool with you.

For the most part this is not a big problem since the battery lasts so long, and users typically wouldn't get into a situation where they need to do this in the field.

holosun 507c x2 battery tray screw

Just becareful not to lose the battery tray retainer screw because its very small.

Rock Solid Body Construction

holosun 509t on walther pdp 9mm

Most Holosun optics are 7075 T6 forged aluminum, but the 509T is titanium and its fully enclosed emitter design to keep out dirt water.

Holosun 509T has a decent durability rating for its price range.

It can survive:

  • Drop
  • 5000Gs of vibration
  • Repeated recoil to hold zero
  • Slide racking
  • Every day carry wears and tears

Based on our initial testing, the difference between 7075 T6 and titanium is hard to tell at this point of the review process for less than 500 rounds, but please check out Sage Dynamics 10K round test:

Turret Adjustment

Holosun 509T 0.5 MOA / Click adjustment, and this offers slightly finer reticle adjustment just a hair to get on target.

This makes the optic a great choice for rifle and PCC applications as well.

kriss vector with holosun 509T

Just like other Holosun products,  the elevation and windage adjustment knobs are recessed to prevent accidental adjustments.

Unique Different Mounting Platform

holosun 509T bottom view mount footprint

For most full size MOS ready handguns, this is a completely new mount footprint other than the RMR footprint.

So the users have to buy aftermarket 509T mount adapter to make it work. Some gun companies are already making adapters for it, but some don't.

holosun 509t rmr adapter plate

The good news is that there is an included RMR plate adapter to go on any RMR footprinted pistol slides or optic mounts, so the 509T can clamp on there.

scalarworks leap with holosun 509t

The best place to get adapter plate is CHPWS. They offer plates for various handguns such as Glock, HK VP9, STI Staccato Duo, Walther PDP, Sig P320 and many more.

Use For Conceal Carry

walther pdp with holosun 509T

The size of the 509T isn't much bigger than the 507C, and it works for conceal carry users. 

The part we like the most is the closed emitter design keeps dirt, hair, fluid and other debris from falling into the optic when it's in a holster.

Final Verdict

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If you have been looking for a duty grade closed emitter red dot sight, the 509T is here to serve you. It works on pistols and rifles.

At this price point, the 509T is durable for its price range, and it's much cheaper than the Aimpoint ACRO and the field of view is larger for pistol applications.

To summarize:


  • Titanium body with closed emitter body design to keep debris away from the emitter enclosure
  • Great for carry
  • Smaller than Aimpoint ACRO
  • RMR adapter plate included
  • Non snag body profile
  • 32 MOA circle helps dot tracking even if the dot is slightly off center
  • Side battery loading without sight removal


  • Need a super small flat head for dial and battery tray access
  • Need to buy custom aftermarket 509T mounting plates for specific pistol slides