What is parallax?

Take your two index fingers.  Place one about 6 inches from your nose and the other one at arms length.  Line them up.  Now move your head.  It looks like your finger moved.   The same thing happens within a firearm optic.  If you move your head too far, the point of impact will change.

What is parallax free?

Some manufacturers will say their optic is parallax free.  When you look at the fine print, this is true only from 50 yards out.  If you aim at something closer is your eye is not in the centre, then your point of impact can change.  This can cause a problem if you are shooting at something close in like a turkey or a squirrel.  But in bullseye handgun shooting on a 50' range this can be a big problem.  Holosun technology is parallax free from 25 yards!

Why is the front objective lens angled?

The angled objective lens is part of the design.  All red dot sights have to have a bit of an angle on the objective to allow for the light from the LED emitter to bounce off the inside surface and be reflected to the shooter.

The Holosun design is a bit steeper than many and this allows for the emitter to have an extremely low profile so that it does not intrude into the inside of the tube and obstruct your view.   The angle also reduces reflection to your target.

My new HS510C isn't working

If you have purchased a new HS510C and you are seeing symptoms such as the the reticle not turning on, blinking, or other odd behaviour, there is a simple solution.   

The HS510C contains a super capacitor.   It allows the sight to function even in the dark for several hours without a battery.   If the sight has been stored without a battery for a period of time, the super capacitor can become discharged.   Please place the HS510C in sunlight or bright artificial light for a couple of hours.    This should address the issue.

How do I adjust the auto sleep mode? (Shake Awake)

Certain recent production sights have an updated motion sensor and new options for the auto sleep mode.

The default sleep timer setting is 10 min, but can be adjusted
1) Press and hold the “+” button for 10 seconds to enter time adjustment mode. There are 4 options: 10 min, 1h, 12h or the sleep mode is disabled.
2) Press and release either “+” or “-” button to set the time. The LED will blink (1=10 min,2=1h, 3=12h, or4=disable sleep mode.
3) Press the “+” and “-” buttons simultaneously to save the time setting and power off the sight

Why is the dot/reticle on my Holosun sight blurry?

The reticle on Holosun sights is widely held as one of the sharpest in the industry.  Even sharper than the market leaders.   This is the feedback that has been given at multiple SHOT Shows by hundreds of industry members. If the shooter has un-diagnosed or under-corrected astigmatism, the dot may appear as a series of dots, starburst,  a smear, or a coma shaped dot.  If the shooter has used other red dot sights, the dot on those sights may not have been as sharp and thus masked the vision issue.  Each sight goes through quality assurance tests at the factory and then we test the sights again when we import them into Canada.  Please have someone else look at the dot to determine what they see.  

A quick Google search will yield some interesting discussions.    https://www.google.ca/?gws_rd=ssl#q=red+dot+sight+astigmatism

Are your optics just a Chinese clone?

Holosun Technologies has been an Original Equipment Manufacturer to many top brands for years.  Holosun has their own research and development engineers working tirelessly to bring new technology to market.  Innovative features like battery life of up to 50,000 hours, the quality of the optics, low parallax, solar power, and the motion power on feature are as good as or better than the competition.

Why is the HS403A battery under the mount?

With Holosun technology including power management functions such as automatic power off, it is expected that the battery will last 50,000 hours of active use.  You should rarely need to replace the battery.  In fact it should last about as long as its shelf life.  If you do need to replace it, use a high quality lithium cell like that which was supplied.  You may need to re-zero after remounting your optic, but it should be very close.

Do you have any hints for attaching the HS403A mount?

You need to remove the mount to install the battery or to change from high mount to low profile mount.  Use the small Allen or Torx wrench to remove all four screws. Set aside the screws. Install the battery or change the mount as needed.  Carefully place the mount onto the scope and then reattach the screws so that they are barely hand tight.   Now tighten the screws gradually a bit at a time, first one screw, then the one diagonal to it.  This is to ensure the screws are evenly tightened.  You should hear the screws "squeak" a bit when then are tight.  For a new optic, if you have the time, let the scope sit overnight and re-tighten the screws the next day.  As the rubber gasket that protects the battery may compress a bit.   You can also use a low strength thread locking compound like Locktite Purple(tm).  Loctite or a similar thread locker should be used with any of the Holosun sights.

Why did you use a Torx screw in the mount?

The Torx wrench can provide far more torque than an normal hex Allen wrench. Holosun used this particular hardware to ensure that the optic is mounted as robustly as possible.

Can I adjust the 8 hour time before the red dot powers off (applies to non-solar models)?

You sure can.  When you hold "+" button for  more than 3 seconds it will go to auto-shutoff hours adjust mode, the red dot will flash 8 times(default).  At this time, if you press "-" button once, it will decrease the time one hour, also the red dot will flash once. If you press "+" button, the hour will increase one hour (red dot will flash once).  You can adjust the time from 2 to 8 hours. When you hold "+" button for  more than 3 seconds again, it back to brightness adjust mode (regular mode).   You can verify the current setting by holding the “+” button for more then 3 seconds.  The number of flashes will indicate the number of hours.  e.g. 3 flashes = 3 hours.

What is this red reflection that I see inside the optic?

This is a product of the red dot / reflex optic technology.  It is a common issue to many manufacturers.  It will become more pronounced if you have the sun at your back.  It does not affect the accuracy though.

How come the objective lens is red?

This is a proprietary lens coating technology that enhances the brightness of the optic.  Call it their secret sauce!

Which side of the battery is positive (+) and which is negative (-)?

The side with writing on it is usually the positive side.  On models with the battery tray, the (+) side should face down.

How much recoil can the sight withstand?

Holosun sights have been bench tested to 1000G. There are numerous tables online that show the recoil of various calibers. The recoil the optic experiences can be affected by many factors. A semi-automatic vs a bolt action will experience different recoil. The weight of the firearm also affects the G forces experienced by the optic.  Please see this page for further explaination.


Why have I seen Holosun talked about on Airsoft forums? Airsoft is like any any other shooting sport, participants want to have whatever competitive advantage they can afford.  Holosun offers high quality, reasonably priced optics that give that advantage. While Holosun optics are designed for firearms, they have performed well in Airsoft competitions.   Also, people are now finding the recoil from gas blow back airsoft rifles is enough to destroy replica Airsoft optics.  Holosun optics don't have this issue.

Will painting my sight affect the warranty?

Painting, hydro dipping or applying other finishes to a Holosun Technologies sight will not automatically void the warranty. Should a warranty issue arise, and it is determined that the after market finish was the cause, then the warranty claim will be denied. If the warranty issue is independent of the sight being finished, then normal warranty terms will apply.  Please take an image of the sight before you apply the finish to record the model and serial number.

Energizer CR2032 Cell Product Safety data Sheet

The Product Safety Data Sheet or PSDS for the Energizer CR2032 cell supplied with each sight in Canada can be found at http://data.energizer.com/PDFs/lithiummangdioxide-coin_psds.pdf

Why is my front lens off-axis?

Red Dot Lens Positioning: All red dot sights have an objective lens at the front of the unit that is spherical in shape. However, unlike a conventional riflescope, the objective lens in a red dot sight is positioned off axis and appears to be tilted when looking at the sight. This angle of the front lens allows the light generated by the battery powered LED light source inside the unit to be reflected back into the sight. The reflected light becomes the “dot” or aiming reference that the user sees when a red dot sight is switched on. This engineered “bending” of light is what makes today’s red-dot sights so popular and easy to use. Adhesive is used on the inside of the sight to secure the LED to the inside of the tube. By design, the led package intrudes slightly on the field of view.


How do the solar optics work?

In automatic mode our solar optics automatically switch to battery power whenever there is not enough light available to power the reticle. In manual mode, the optic will always use battery power. The “solar panel” on top of our optics is actually a photo-diode array (basically a light sensor). It controls both the auto brightness adjustment and provides solar power to the product. Sometimes our customers try to test if battery power is working by covering the panel to see if the reticle will still be there. The problem with that test is that you trick the optic into thinking that you are in very low light conditions. The optic then lowers the reticle intensity down to night vision mode, which means that the user is unlikely to see the reticle in normal lighting conditions. The best way to test if the battery is taking over is to go into a pitch black room and see if you still get a reticle. (In darkness, you should be able to see the night vision intensity setting.) Since the solar panel is also the light sensor, be careful not to cover it up when testing reticle brightness. Also, keep in mind that the reticle intensity will be set to the lighting conditions of the shooter, not the target. If the target is in very different lighting conditions, you should switch the optic to manual mode and adjust the brightness to the appropriate level.

How should I zero my optic?

Caution: Make sure your firearm is handled safely at all times exercise proper range safety procedures. Seek advice from a qualified firearms instructor if you have any questions about this procedure or how to handle your firearm. Each click on our windage and elevation turrets is equivalent to 1/8” at 25 yards; 1/4” at 50 yards; and 1/2″ at 100 yards. Please download our zeroing target, set it up at your chosen distance, and shoot one group. count the number of 1/4″ squares you need to move horizontally and vertically to achieve a bulls-eye and then make the appropriate adjustments. Turning the elevation turret counterclockwise will move the point of impact up. Turning the windage turret counterclockwise will move the point of impact right. Turning either turret clockwise will produce the opposite shift in point of impact. Once adjustments have been made, shoot another group. Repeat as necessary until you are satisfied with your zero. Don’t try to over rotate the turret adjustments. If adjustment begins to require more force, you have reached the adjustment limit and forcing further adjustment may damage the device.

Recommended zeroing distances?

Most people tend to zero somewhere between 25 and 100 yards. This is really a matter of preference and it is often best to consider what your philosophy of use for the firearm is when you decide on a zeroing distance. For example, someone interested in self defense, might zero at 50 yards or less, while someone looking to do short and long distance range shooting might zero at 100 yards. Seek the advice of a qualified firearms instructor to best understand what zeroing distance is best for you.

Product nomenclature basics

HS = Holosun; 1st digit = 4 for 2 moa dot only reticle, 5 for 2 moa dot with a 65 moa circle reticle; 2nd digit = 0 for standard accessories, 1 for upgraded accessories (kill-flash filter, Quick release mount and flip lens covers), 3rd digit = 0, 1 or 2 for an infinity 30 mm tube red dot, 3 for a micro red dot Final letter = C for solar, all others for battery powered only.

Do Holosun Optics Co-Witness?

Yes. All of our infinity sights are set up for a lower 1/3 co-witness on standard AR sights. Most of our micro dots come with a high mount, which is suitable for a lower 1/3 co-witness on standard AR sights and a low mount which is suitable for an AK, shotgun or a pistol. We also sell an absolute co-witness mount designed for standard AR sights, which is compatible with the HS403G, HS403GL, HS503FL and HS503GU.

Which Holosun Optics are compatible with the AACW1.4 absolute co-witness mount? Except for the HS403A, all of our micro red dots will fit on our absolute co-witness mount. That said, the unit is designed specifically for the HS403G, HS403GL, HS503FL and HS503GU. Those are the only optics that will achieve an absolute co-witness height on the mount.

Which Holosun Optics are compatible with the quick release mount?

The HS403B, HS403C, HS503C, HS503CU, HS515C, HS515CU, HS503BU, and HS515BU

30mm tube dot vs micro dot… Which one is better?

This is a matter of preference. A few trade-offs between these optics are weight, tube diameter, mounting versatility and looks. Feel free to contact us if you are having trouble deciding what works best for your application.