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Holosun HS507K-X2 Compact Pistol Red Dot Sight - Red ACSS® Vulcan® Dot Reticle

Manufactured by Holosun
Manufactured by Holosun
15 Reviews

In Stock

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Made as a collaboration between Holosun Optics and Primary Arms Optics, the red-illuminated HS507K-X2 with patented ACSS® Vulcan® Dot Reticle brings the revolutionary Vulcan aiming system to a micro reflex footprint.

Designed for concealed carry, the HS507K-X2-ACSS is lightweight, durable, and dependable, with up to a 40,000-hour runtime on medium settings. This sight retains all the core features and technologies of the standard Holosun model, including the Multi-Reticle System, Shake Awake technology, and a built-in Lock Mode. With 12 red-illuminated brightness settings and intuitive push-button controls, the HS507K-X2-ACSS works in any lighting condition and is even compatible with night vision devices.

The ACSS Vulcan Reticle is a revolutionary approach to reflex sights, giving the optic AutoAim™ functionality by improving user agility through a ‘heads-up’ target acquisition. Under duress, standard reflex reticles can be lost without proper sight alignment. With the ACSS Vulcan reticle, users always know the relative location of their aiming point, allowing for quick correction and improved accuracy on target.


  • Red-Illuminated patented ACSS® Vulcan® Dot Reticle System
  • Ultra-compact size for concealed carry applications.
  • Two Reticle Settings: Dot + Circle, and Dot only
  • Shake Awake™ - Motion on with last setting recall.
  • Parallax-free, unlimited eye relief.
  • CNC milled 7075 Aluminum Housing.
  • 10 daylight and 2 night vision compatible brightness settings.
  • IP67 Certified.
  • Holosun K footprint (modified RMSc)

This co-branded optic features the patented ACSS® Vulcan® Dot reticle system, which improves acquisition and recovery speed through its patented outer reference circle. When aimed on-target, the ACSS Vulcan Dot reticle appears as a simple, unobtrusive 3 MOA dot. When your aim is off-target, the edge of the 230 MOA outer circle guides you back to center. ACSS Vulcan Dot alleviates one of the main weaknesses of micro reflex optics, ensuring you can always find your reticle aiming point, despite the smaller optical aperture.

This version of the optic uses RED reticle illumination. Red illumination is better for low-light and nighttime as it preserves your natural night vision. Red also contrasts more against many natural backgrounds, such as dense foliage. For GREEN illumination, the HE507K-GR-X2-ACSS offers the same features but with a green LED emitter.

The HS507K-X2 with ACSS Vulcan Dot Reticle features a modified RMSc footprint. While the screw slots and recoil lugs are the same, the overall dimensions of the red dot base are slightly different and may not fit some slides milled for the RMSc optic. It does mount directly to the P365X/XL slide.

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Battery Life25,001 - 50,000 Hours
Battery TypeCR1632 3V Lithium Coin
Brightness12 Settings
Click Value1 MOA
FinishHardcoat Anodized
MaterialAluminum - 7075-T6
Mount CompatibilityHolosun 407K/507K
Night Vision CompatibleNight Vision Compatible
Reticle ColorRed
Warrantylimited lifetime
Weight1.0 Oz
California Prop 65 warning

 WARNING: This product can expose you to chemicals, which are known to the State of California to cause Cancer and Reproductive Harm. For more information go to www.P65Warnings.ca.gov.

Ratings & Reviews

15 reviews

  • 3 stars
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  • 1 star
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Crisp dot and works great!

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Initially I thought this was the ACSS chevron radical. To my surprise, it was not. After my trip to the range, I was impressed on how quickly I was able to find the dot with the outer ring. I would highly recommend this product to anyone interested in a red dot optic.

Holosun 507K ACSS Reticle

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Exaclty what i'd been waiting for...a lightweight K size dot with the PA ACSS reticle. Very happy with it!

Works as advertised

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It was remarkably easy to find the dot and put it on target.

Great compact Red dot

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Amazing red dot with ACSS - a must have for single stack or compact pistol for conceal carry. 30 years military experience with weapons and this new technology is the best.

Great Compact RDS

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This RDS is super for a carry pistol. Since the window is small, it is very convenient to have a circle around the dot to make acquisition of the red dot easier.

I have no idea why I waited to buy this...


Just buy it, you're not going to be disappointed. I'm at least a half-second faster on my draw to first shot time and I literally slammed it on the table at the range like a hammer at least a dozen times before putting down a 2" group at 40ft with a Glock 43 as if I was trying to get that PA sponsorship. She's good to go guys.

Great reticle

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First experience with ACSS reticle. Great improvement.

A great value with even better service.

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This is the second Holosun sight that I have purchased from PA.

For years I avoided red dots on pistols because it was so easy to lose the dot.
That's not an issue with this sight, because the 250 MOA ring always guides you back to the dot.
Putting the dot on the target is now effortless.

But better than that is the fast service I get from PA.

I'll go to them first for my next purchase.

Acss doesn't dissapoint

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I needed a smaller footprint optic for a Canik pistol. I also prefer the ACSS reticle as it is faster and a more efficient way to pick up the center of the reticle. Monte’s just fine and I had almost no adjustment for a 25 yrd zero. I wish it was closer to the 507k with the chevron reticle and a slightly larger window. I realize it is for a CCW but with more full-size pistols using the RMRcc footprint a second 507k version with a larger window would help.
Overall I’m very pleased with the function of the reticle and optic.

Pretty good, but some considerations.


I had a similar Holosun red dot (actually a ‘red’ dot) on my Hellcat EDC. It was pretty beat up so I switched up to the ACSS/Green dot version.

Some considerations. First, depending on the user’s skill, the ACSS circle may or may not be helpful. I’ve found it to be not as helpful as I practice quite a bit and can present the optic on target quite quickly. However, newer shooters may find it helpful. Second, this sight is NOT a ‘Dot / Circle Dot’. There is no ‘circle’ for the target, just the green dot and the very large ACSS circle. Third, I see no advantage to a green colored dot over a red colored dot. Perhaps if the target is in dark colors, in dim light, etc. But, for me, there appears to be no advantage to Red vs Green. Finally, the green color ‘washes’ out the glass more than the red. It’s not a big deal, but there is some background green wash over the entire glass that doesn’t exist in a red dot, which would be red, of course. Perhaps that’s because of the ACSS.