Holosun HM3X Red Dot Magnifier with QD Mount

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Holosun 3x Magnifier – HM3X

The Holosun HM3X enhances the view through your red dot sights with 3x magnification on demand. This red dot magnifier comes with a QD mount to attach securely to your rifle, with a switch-to-side hinge that easily locks in just with a push or pull. The glass has excellent clarity, with 2.75 inches of eye relief for an ideal eyebox on your AR-15.

Simply attach the HM3X behind your red dot sight, use the flush windage and elevation turrets to center the reticle, and you’re good to go.

Which Red Dot Should I Use?

The HM3X comes usable out of the box with Absolute Cowitness red dot sights, and can be adapted for Lower 1/3 Cowitness using an included spacer. If you’re running a 510C (Absolute Cowitness), you can use the HM3X with no modifications needed. For a 503CU with Lower 1/3 Cowitness, simply add the spacer under the magnifier body.


  • 2.75 inches of Eye Relief
  • Switch-to-Side QD Mount
  • Switchable for Absolute to Lower 1/3 Cowitness using Included Spacer
  • Perfect match for Holosun 503CU and 510C Red Dot Sights


  • QD Release Mount
  • Lower 1/3 Cowitness Spacer
  • T10 Wrench
  • User Manual


  • Magnification: 3x
  • Objective Lens Diameter: 28mm
  • Eye Relief: 2.75″
  • Housing Material: 6061-T6 Aluminum
  • Dimensions
    • Height: 2.42″
    • Width: 1.66″
    • Length: 4.03″

Have Questions About this Product?

The AT3 Tactical store has a 90 day no-hassle return policy for products in good condition. You can view the full details of our return policy here.

If you encounter an issue or defect with a product after 90 days of your purchase, you can refer to the manufacturer for a warranty claim. Their policies are below.

Your Holosun product is warranted to be free of defects in materials and workmanship to the first owner upon registration of the product. This warranty specifically applies to the metal structure, optical and illumination systems. The metal structure/housing and optical system (glass) of your Holosun product is warrantied for the life of the product under normal, personal use. Under the Holosun Warranty, the illumination system (LED), is warrantied for 10 years from the manufacture date under normal, personal use. In the event of a confirmed defect under this warranty, we will, at our option, repair or replace the product with a Holosun product of similar type/function, and of equal or greater value. Holosun reserves the right to make substitutions for similar product/s if the warrantied model in question is no longer in production. This Holosun Warranty does not apply to: (a) asserted defects caused by normal wear and tear of any part including knobs, finish, etc.; (b) asserted defects caused by modification including; aftermarket finishes, unauthorized service, improper maintenance, acts of Nature; and (c) asserted defects involving subjective personal likes or judgments. Also, this warranty is null and void if modification or maintenance is provided by someone other than Holosun. Holosun may restrict warranty service for our products to the country from which Holosun or its authorized dealers originally sold the Holosun product. For warranty claims outside the United States, the costs of shipping or transporting the product (including to and from Holosun or our dealer), any insurance or any fees, duties and taxes are the sole responsibility of the purchaser and will not be covered by this warranty.

Registration is required to validate this warranty. For product registration click here. For a warranty claim, click here.