Holosun 509T: Red Dot Reckoning at a Thousand Rounds


It took a while, but the Red Dot Sight (RDS) is now widely accepted as a suitable accessory for a defensive handgun. And while the RDS market was dominated by just a couple of big names for a very long time, the last couple of years have seen several new optics companies reach a level of mainstream use. The most popular of these newcomers is probably, as of this writing, Holosun. I recently completed my first thousand rounds through the 509 Holosun RDS and, with just one minor aggravation, found it to be an excellent Red Dot Sight option. 

Holossun 509T RDS

by Daniel Bales

The HE509T-RD (red reticle) is an enclosed reflex optical sight designed to be mounted to a pistol. The 509T features include a Titanium housing, Holosun’s proprietary “Super LED” with what they say is up to 50k hours of (CR1632 coin) battery life, and some other features those who’ve used Holosun will be familiar with: their Multi-Reticle System, Solar Failsafe, and Shake-Awake Technology (q.v.). As an optic with an enclosed emitter, it’s not quite the same sort of Holosun red dot many shooters might be used to, though the controls are intuitive and easily manipulated. As a result, many people justifiably compare it to the Aimpoint Acro.

One particularly likable attribute is its battery access. The optic is designed to swap batteries through a tray without removing the sight from the gun.

Colors and Contrast on the Holosun 509T

Available in both a red and a green reticle, the Holosun 509T has 12 different brightness settings. These include dim settings compatible with night-vision devices. The 509T has what they describe as a parallax-free design, with unlimited eye relief (though no optic is completely parallax-free). In addition, the 509T’s “Shake Awake Technology” shuts the LED off during periods of motionlessness.

The Holosun 509T
The dot intensity adjustment buttons on the 509T are large and easy to use.

The amount of time it takes for the LED to deactivate is user-programmable. Shake Awake can also be completely deactivated, which keeps the optic powered on for up to 100k hours.

This HS model also includes “SOLAR FAILSAFE technology.” This feature automatically adjusts the sight’s brightness. Thus, when the optic is in a lit environment, you will have a bright reticle; when indoors, it will automatically dim to match ambient lighting conditions.

The Holosun 509T
The Solar Failsafe is an excellent addition to the 509 and allows the optic to run on a failed battery.

Solar Failsafe will also allow the red dot sight to remain powered when your battery fails.

Mounting Up with CHPWS

I choose to mount the Holosun 509T to my Gen 5 Glock 34 MOS. To accomplish this, I used CHPWS 509 red dot adapter mounting plate. I have been using the C&H Precision Weapon Systems (CHPWS) plates for some time; they are a trusty and sturdy option for anyone using a plate-mounted RDS pistol. Let me talk about the CHPWS 509 plate for a minute.

CHPWS describes the GLOCK MOS adapter plate as the “…most rugged, reliable, and trusted red dot adapter plate on the market today.” My experience gives me no reason to doubt it.

They further advise that their adapter plates are approved for duty use by several hundred Local, State, and Federal law enforcement agencies and some US Military units.

Mounting the CHPWS 509 plate to the Glock 34 MOS is a relatively simple process. To accomplish this, I removed the old plate and placed the CHPWS 509 plate in its place. Next, I utilized the (included) mounting screws and Vibra-Tite thread locking liquid, then torqued it to their suggested torque specs.

After mounting the plate, you can place the 509T on top of the plate and tighten the mounting screw on the optic. This mounts the optic to the plate and pistol, though you’ll still have to zero the weapon.


Adjust and Zero

Before I go to the range, I will adjust the red dot to the co-witnessed iron sights. To do this, I look through the optic, align the iron sights appropriately, then adjust the RDS up, down, left, or right until the dot is sitting directly on top of the front sight.

This is not a zero!

It is just moving the dot closer to actual zero, so I use less ammo during the zeroing process.

My thousand round count (and counting) experience with the olosun 509T by completing my zero. I zero all pistol-mounted optics at 25 yards, starting from the 10-yard line. I’ll fire anywhere from three to ten rounds and attempt to obtain a reasonable group with those rounds. If the group is off, i.e., if the group is low and left, I adjust for POA/POI (point of aim/point of impact).

After achieving my desire from 10 yards, I move to the 25-round line and repeat the process. Usually, the completion of these two steps will end with the topic being close to or right on my desired zero., 

Completing the zero was extremely easy with the Holosun 509T. The windage and elevation adjustments have an excellent audible click with a firm movement between clicks. Each click on the windage and elevation on the 509T is 1 inch at 100 yards, so at 25 yards, you are moving ¼ of an inch per click. As a result, I was able to achieve zero using only a few rounds.

While zeroing, I use a B-8 target and my point of aim is the X ring.

Note: the reason I complete my zero at 25 yards is that it is more precise. If one can achieve a quality zero at 25 yards with a pistol-mounted optic, it will be better than a zero at 15 yards. I have noticed this with individuals who zero their pistol optics at 10- or 15-yards. Such results are good at those ranges, but when you step back to 20 and 25 yards (or even further), there is a degradation in achieved accuracy. So by zeroing back at the 25, I can ensure I’m more likely to hit what I want to hit from the 25 and in. 

Doing It with the Dot

I used the first 50 rounds with the Holosun 509 to complete the Dot Torture shooting drill. I typically complete this drill* at 3, 5, or 7 yards, and every string of fire started from the holster, and this time was no different.

The first 50 rounds fired after my zero, completed using the “Dot Torture” drill. I finished this 50/50 at the 3-yard line. 

The Holosun 509T has a 2 MOA dot that is clear and crisp. Although I was shooting outdoors in bright desert sunlight, the dot was easy to acquire and maintain. This is complemented by the optic’s closed emitter housing, the structure of which provides an aiming reference aid.

If you look through the 509T and see the side, top, or bottom of the housing, you need to adjust your firing grip. Correctly done, this will help you look directly through the two viewing windows with no sides in view and should allow you to readily “pick up” the dot inside the window.

I utilized several drills to test the Holosun 509T, including the dot, as mentioned earlier, Torture. Another, pictured here, is the “5×5”. The 5×5 drill is an excellent way to test both skill and equipment.

While evaluating the Glock 34 with 509T mounted on it, I have completed the following shooting drills: FBI QIT, FBI Bullseye Qual, Half and Half, The Super Test, 5×5, and others.

The optic remained zeroed, the dot remained visible, and the optic remained mounted properly through all those shooting iterations. The optic has been mounted for approximately four months now, and I’ve yet to change the battery.

There are many things to recommend the 509T. Some that stood out for me were:

• Bright dot intensity

• Easy and audible elevation/windage adjustments

• Rugged housing

• Battery tray allowing battery change without optic removal.

• Ability to choose three reticle choices, i.e., 2 MOA dot, 2 MOA dot with 32 MOA circle, and 32 MOA circle.

 The only negative I’d call out in this stage of my evaluation is that windage and elevation adjustments require a tool supplied by Holosun.

If you are looking for an optic for your pistol, particularly if you have a limited budget, I would strongly recommend you consider the Holosun 509T as an option. As of this writing and round count, it is at the top of my list in a market full of RDS options.

Note: Plate Particulars

CHPWS plates are designed and manufactured in the USA. They’re CNC Machined from Aircraft Grade 6061 Aluminum with a Type III Hard Anodized Finish and come with Stainless Steel Torx Head M3 screws to mount the plate to your slide. Each plate comes with a lifetime warranty against manufacturing defects. Read my CHPWS review online here. (Online at CHPWS.com; connect via Facebook /CHPWS/ or follow @chpws on IG; #boomsquad on Instagram.)

Holosun 509T Manufacturer Specs

The Holosun 509T is an enclosed reflex optical sight designed for pistol applications. Features include a Titanium housing, Holosun’s Super LED with up to 50k hours battery life, Multi-Reticle System, Solar Failsafe, and Shake Awake.RMR

The included 509T-RD RMR adapter plate is not compatible with ZEV or Shadow Systems style RMR interfaces.

    • MRS: Circle Dot; Dot Only
    • Up to 50,000 Hours Battery Life (Setting 6)
    • 12 Brightness Setting: 10 DL & 2 NV Compatible
    • Enclosed Design & Titanium Housing
    • Convenient Tray Battery Compartment
    • Parallax-free & Unlimited Eye Relief
    • Solar Failsafe
    • Shake Awake
    • Multi-Reticle System
    • Super LED
    • Reticle2 MOA Dot & 32 MOA Circle
    • Light Wavelength650nm
    • Reticle ColorRed
    • Parallax FreeYes
    • Unlimited Eye ReliefYes
    • Magnification1x
    • Multi-Coatings
    • Power SourceSolar & Battery
    • Battery TypeCR1632
    • Battery Life (Hours)
    • Housing MaterialTitanium
    • Surface FinishTitanium
    • Adjustment per Click1 MOA

The optic ships with:

• RMR Adapter

• User Manual

• Lens Cloth

• T10L Key

• CR1632 Battery

About the author: Daniel has been in law enforcement for nearly 15 years. During his career he has worked for a large Sheriff’s department in Nevada on such assignment as detention, courts, court transport, patrol, and S.W.A.T. He is currently a full-time rangemaster. Daniel has numerous firearms, tactics and instructor certifications, to include: handgun, shotgun, carbine, less lethal, force on force, low light, certified armorer, basic and advanced S.W.A.T. schools. He has instructed many students for LMS Defense and is one of the founder-owners of Crucible Consulting. Follow or connect via Instagram, @crucible_consultants.

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