Holographic Weapon Sights FAQ

Will the HWS hold zero as temperature changes?

EOTech’s sights experience a point of impact shift away from the point of aim when the sight is exposed to a temperature different from the temperature at which the sight was zeroed. After zeroing the sight at or near ambient temperature (73°F), the zero position will shift during operating temperature changes. For sights manufactured after October 2016, the typical shift will be between approximately 1.4 and 1.8 minutes of angle (“MOA”). Due to manufacturing variations, however, a particular sight has the potential to shift a maximum of approximately 3.5 MOA at -4°F and 122°F. Sights manufactured prior to October 2016 have the potential to shift approximately +/- 5 MOA at -40°F and 122°F.

Due to thermal drift, sights may not return to zero. The sights have the potential of approximately a +/- 2 MOA zero shift upon return to ambient (73°F) after being exposed to any temperature between -40°F and 122°F.

Shifts result from natural thermal expansion or contraction that is present in various materials as they are heated or cooled, and is greater the more extreme the temperature change. For example, when a sight is zeroed at 73˚ F then acclimated to 50˚ F, less shift occurs. On the other hand, if zeroed at 73˚ F, then acclimated to 0˚ F, more shift occurs. The shift may not be significant to shooters who use their sights at close-quarters ranges. For instance, 3.5 MOA is a shift of .875 inches at 25 yards, and is 3.5 inches at 100 yards. It also is worth noting that thermal effects are evidenced to varying degrees in common optics, as well as in rifle barrels and ammunition as the environmental conditions change. In all events, to achieve optimum accuracy, the sight zero should be verified whenever the sight is exposed to marked temperature changes, and the sight should be re-zeroed as necessary.

Does the HWS have parallax?

All optics experience varying degrees of parallax depending on use and operating conditions.  Parallax is an apparent change in the point of aim resulting from a change in the position of the shooter.  EOTech’s sights have little parallax when the reticle is in the center of the viewing window, which is the optimum sighting position and also is the correct place for zeroing the sight.  On the other hand, if the user is looking through the sight at the outer edge of the sight window – an off-axis view – the parallax error might be up to 4±3 MOA (or a total of 14 MOA across the viewing window) at 71˚ F (for a sight properly zeroed).  In other words, parallax can increase as the user’s view approaches the edge of the EOTech viewing window.  To put this possible amount of off-axis error into perspective, 7 MOA equates to 1.75 inches at 25 yards or 7 inches at 100 yards.  Viewing through the center of the window achieves the least parallax error.  Parallax may increase as temperature changes from 71˚ F.  At operating temperature extremes of -40˚ F or 122˚ F, there may be an additional 4 MOA of parallax.

Can EOTech HWS handle harsh recoil?

EOTech sights are designed and tested to withstand punishing recoil from a variety of firearms.  HWS units have been used on the military's M2 .50BMG machine gun, Smith and Wesson .500 and .460 pistols in Africa, shotguns of all sizes, and can even handle the reverse recoil found in air guns and crossbows.

How does the HWS compare to red dot sights?

Please see the holographic sight vs. red dot sight page of this website for a comparison.

For what tactical applications can the HWS be used?

Typical tactical applications are with shoulder-mounted small arms weapon systems, such as these:

  • MP5-style sub guns
  • M4/M16 and derivatives
  • Tactical shotguns

The HWS is also used extensively on less-lethal launching platforms:

  • 37 mm and 40 mm
  • Shotgun applications involving bean bag rounds
  • Rubber bullets
  • Deployment of gas munitions

Other applications include:

  • Medium-caliber (.50) machine gun weaponry
  • Shoulder-mounted rocket launchers
  • Grenade-launching platforms

In all cases, HWS greatly enhances speed, accuracy, ease of use, and vision maintenance.

What are the advantages of HWS for Close Quarters Battle (CQB)?

Advantages of EOTech’s HWS for CQB include:

  • Speed – The HWS is considered, by most, to be the fastest sight on the market today.
  • Vision – Maintenance of the operator’s peripheral vision, with the tubeless HUD architecture and 2-eyes-open shooting.
  • Ease of use – This leads to incredible accuracy, which provides the operator with controlled confidence in his shooting ability.

Can I use the HWS for long-range engagement?

Yes. The HWS can be used with extreme accuracy for engagement to 300 meters.

The HWS provides a much greater field of view than a magnified scope, providing the operator with more visibility in a tactical engagement area.

However, the clear objective advantage is in close-quarters battle (CQB) situations, in which speed is a must. The HWS is an obvious choice for an M16 or M4, weapons used for both CQB and longer-range engagements.

Need to increase your visability for longer range shooting? Look at partnering the HWS with our G33.STS magnifier. With a magnification of 3x and an adjustable diopter, the target will be in clear focus allowing the operator to make a more precise shot.  The switch-to side mount allows for incredilby fast transition times between close quarter and mid to long range shooting making this combination the best of both worlds.

Is any light that can be seen cast on the target?

No, there is none. Unlike a laser or red dot sights, the holographic image projects no forward light onto the target. So there is no position-revealing light.

The projected reticle is visible only to the operator. The operator remains completely hidden down-range, even from night vision systems.

In addition, there is no muzzle-side reflective glare from coated lenses like on red dot sights, scopes, or binoculars. The HWS does not need any costly add-on filters that would also significantly reduce the effective light transmission and make the target less visible.

Is the HWS water resistant?

Yes. EOTech HWS are water resistant. The depth to which each model can be submerged varies.

What is minutes of angle (MOA)?

MOA stands for minutes of angle.

  • 1 MOA is nearly 1 inch at 100 yards.
  • The center dot in the standard reticle is 1 MOA across.
  • The ring in the standard reticle is 68 MOA across.

The windage shaft and the elevation shaft on your HWS move in approx. half-MOA increments. This means every tactile click or single adjustment of the shaft moves your point of aim approx...

  • 1/2 inch at 100 yards
  • 1/4 inch at 50 yards
  • 1/8 inch at 25 yards

How is the HWS mounted?

The HWS is equipped with an integral mounting platform to interface directly with any standard 1 Weaver dovetail or Picatinny Mil spec 1913 mounting rail:

  • Tactical weapons, typically including sub guns, M16/AR15 carbines, and shotguns
  • Weapon platforms with a Weaver dovetail base on the receiver, including M4/M16 flat tops
  • Handguns (although holstering is a problem)

Other mounting options include:

  • Tapping the receiver of the gun
  • Using a non-gunsmithing add-on mounting platform to provide the dovetail base
  • Using cantilever shotgun barrels

Most standard tactical weapons have 1 or 2 mounting solutions, which vary in design. They allow co-witness of the iron sights, access to the iron sights, and cheekweld positions. Make sure to mount the HWS with the battery compartment facing the muzzle and away from the operator.

How to Mechanically Zero an EOTech with M4 Iron Sights

All Eotech sights are designed to co-Witness with iron sights on the standard AR15 platform. Sights with side buttons and/or factory equipped quick detach levers will co-witness in the lower 1/3 of the window. All other models will co-witness in the center of the window. This is based on the model chosen at time of purchase.  

  • Make sure your firearm is unloaded and verified safe.
  • Flip up the iron sights and set the rear sight on the small aperture. You must do this process utilizing the front and rear iron sights, it will not work without a rear sight.
  • With your EOTech turned on, look through the rear peep sight with the front post in view.
  • After obtaining a sight picture, adjust the EOTech so the 1 MOA dot sits directly on top of the front post.
  • Once this is achieved, final zero should be verified using live fire.

Note: When adjusting to iron sights, you are moving the image to the fixed point of aim so your adjustment dials on the sight are in reverse or mirrored.


How to Laser Bore Sight Your EOTech

  • Make sure your firearm is unloaded and verified safe.
  • Insert laser sighting device into barrel and project a dot onto a wall at 21 feet (7 yards).
  • Turn the EOTech on and adjust the brightness settings so the center dot is dimmer than the laser bore projected dot (the center dot on the EOTech will not be used in this process).
  • Adjust the EOTech to the projected laser on the wall and align the bottom of the outer circle at the 6 o-clock hash mark position while looking through the EOTech. Complete the zero with live fire at 50 yards using the center dot for point of aim.

Printable targets to aid with zeroing your HWS

Looking for Targets to aid with the zeroing of your new Holographic Weapon Sight?  Click on the attached PDF files below to find the one best suited for your requirement.