• Post author:
  • Post last modified:December 14, 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 my first 400 rounds. Among all the red dot sights I have tested, this is a very unique red dot sight because its fully enclosed and it has a special clamp mount system that many of my other guns don't have the mounting platform.

Let's check it out.

Holosun 509T Red Dot Sight Review - Core Specs

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

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
q? encoding=UTF8&ASIN=B084Z2768S&Format= SL250 &ID=AsinImage&MarketPlace=US&ServiceVersion=20070822&WS=1&tag=hs509trev 20&language=en USir?t=hs509trev 20&language=en US&l=li3&o=1&a=B084Z2768S


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

As I unboxed it, I couldn't help but notice how solid it looked and felt. The window size, I have to say, is much bigger than what I've seen on the Aimpoint ACRO.

One thing that caught my attention was how they positioned the front lens further back relative to the front, diverting impact stress away. I believe this design choice really enhances its durability.

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

When To Use This Optic

I've found that the Holosun 509T's closed emitter design is a perfect when it comes to concealed carry and outdoor use in various weather and environmental conditions.

I really appreciate the versatility it offers. I can easily mount it on handgun slides, use offset mounts, and even utilize it as my primary optic. What's great is that as it gains popularity, more mounting options become available for purchase.

Now, speaking about closed vs. open emitter red dot sights, I personally prefer the closed emitter design, especially in rainy, muddy, or sandy conditions. It just seems like the way to go for reliable performance.

Holosun 509T 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

For me personally, I find the 2 MOA dot much more useful than having the 32 MOA ring around it. During day time, the single dot provides a much cleaner field of view.

The sight is very fast to pick up especially when I mounted it on the Walther PDP which features 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

The 32 MOA ring size looks very different based on your eye distance to the optic. When I was 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

Get Content Updates & Exclusive Deals

Subscribe to get more content like this + exclusive deals.

From my experience, the battery compartment on these optics is quite user-friendly. You can access it from the side using a small tray, and they provide you with an Allen key to make the process a breeze.

These optics operate on a CR1632 battery, and the best part is that it boasts an impressive battery life of around 50,000 hours. That's a long-lasting power source that you won't have to worry about replacing frequently.

However, it's worth noting a common issue that some users have reported with other Holosun optics – reticle blinking. If you notice this happening, it's usually a sign that the battery needs attention. You can start by replacing the battery, making sure to reinsert the battery tray correctly. If the blinking persists, it's a good idea to check the battery voltage to see if it has dropped below 2.2Vdc, as that could be the culprit.

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. However, so my in my use history, I never had the solar panel kick on because the battery just works and the optic never turned off unexpectedly.

The battery can 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. I personally always lose the tool that Holosun provides me, and whenever I pull the tray out, I make sure that the small screw doesn't get lost.

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

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 my 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 like CH Precision are already making adapters for it. Check them out

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. I used the supplied adapter and mount it to a Scalarworks LEAP RMR mount

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

q? encoding=UTF8&ASIN=B084Z2768S&Format= SL250 &ID=AsinImage&MarketPlace=US&ServiceVersion=20070822&WS=1&tag=hs509trev 20&language=en USir?t=hs509trev 20&language=en US&l=li3&o=1&a=B084Z2768S

If you're in the market for a top-notch closed emitter red dot sight that's duty-grade, the Holosun 509T should definitely be on your radar. From my experience, it's a versatile optic that performs flawlessly on both pistols and rifles, making it a versatile choice for various applications.

One of the standout features, in my opinion, is its price point. The 509T offers remarkable durability considering its cost, and that's a win-win. It's an excellent option for those who want a reliable sight without breaking the bank. Plus, when you compare it to something like the Aimpoint ACRO, you'll find that it's a more budget-friendly alternative that doesn't compromise on quality. Not to mention, it provides a larger field of view, particularly beneficial for pistol applications.

Of course, like any optic, it's not without its downsides. Some users have reported that the brightness adjustment buttons can be a bit stiff and not as user-friendly as they'd like. Additionally, while the battery life is good, it's not exceptional compared to some other models on the market.

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