Holosun Paralow HS503G Red Dot Sight - ACSS CQB Reticle

Manufactured by Holosun
Manufactured by Holosun
112 Reviews

In Stock

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Exclusive to PrimaryArms.com and Primary Arms authorized dealers.

Primary Arms and Holosun have combined forces to bring you the power of the patent pending ACSS® CQB reticle in a red dot sight for the first time! The problem with dot sights is that a large dot is great up close but less useful at distances beyond 100 yards, because the dot becomes too large to aim with precision. A small dot used in conjunction with a magnifier fixes that problem, but is slower to acquire in close range snap shooting. The ACSS reticle uses a large chevron that the eye picks up very easily for up close shooting. At longer distances, the tip of the chevron is an infinitely small aiming point perfect for taking precise shots.
Using "zero" ranges of 25, 50, or 100 yards, the ACSS BDC is compatible with the following calibers:
  • 5.56 NATO / 5.45x39 from 100 to 600 yards
  • 300 BLK / 7.62x39 from 50 to 450 yards
  • 12 gauge 1 oz. slug from 25 to 150 yards
  • 7.62x54R from 100 to 600 yards
  • 7.62 NATO / .308 Win from 100 to 600 yards
  • 300 BLK 220 gr subsonic from 50 to 150 yards
  • .22LR 40 gr from 50 to 175 yards
  • 9mm carbine 115gr from 25 to 200 yards

The ACSS features three BDC dots underneath the chevron, allowing an unprecedented 600 yards of bullet drop compensation in 7.62 NATO or 5.56 NATO calibers. Auto ranging and wind leads are also incorporated into this smart reticle. A CQB horseshoe grabs the eye instantly for close quarters shooting and also approximates the spread pattern of 00 buckshot at 25 yards. The reticle for this sight is a central 2 MOA dot, centered in a 65 MOA circle with four positioning points. The diameter of the circle reticle represents approximately 5'5" at 100 yards 170cm at 100m.

The HS503G is a proven micro dot sight with an auto-on function that switches on the power with a slight movement of the sight. It comes with a 1913 Picatinny base which is removable, revealing an Aimpoint Micro-compatible base underneath. It also comes with the lower 1/3rd co-witness riser mount shown in the photos.
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Battery TypeCR2032 3V Lithium Coin
Brightness10 Settings
Click Value1/2 MOA
FinishHardcoat Anodized
MaterialAluminum - 6061-T6
Mount CompatibilityAimpoint Micro
Night Vision CompatibleNight Vision Compatible
ReticleExclusive ACSS CQB
Reticle ColorRed
Warrantylimited lifetime
Weight4.87 Oz
  • HS503G-ACSS overview with Dimitri Mikroulis
  • HS503G Red Dot ACSS by SuperSetCA
  • ACSS CQB micro explained by Dimitri Mikroulis
  • Holosun 503G Review by MrGunsNGear
  • Holosun ACSS Red Dot Review by Sootch00
  • CountryMash pushes the Holosun ACSS to 500 yards
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

112 reviews


BDC works as advertised


I mounted and zeroed at 100. Immediately moved to the 400 yd target and used the BDC. Right on target!! Awesome product.



FINALLY! After years of research and debate between variable powered optics (1-4x/1-6x) and red dots/holographic sights (aimpoint, eotech, meprolite, etc.) I am proud to say that this one takes the cake with ALL the bells and whistles at half the cost!! Simple, sleek, and durable. Not to mention battery life! We are in the golden age of optics and this one is hard to beat. GET ONE!

Experience with Primary Arms customer service:
After asking to replace the first optic that I had purchased due to a questionable defect Primary Arms was quick to help me at every step of the way in trying to identify the source of the problem and was even quicker at replacing the optic. They even included a sticker! Hahhah why not? Long story short is that the quality control had been tightened up without question and I am still stoked about this optic and its incredible quality both with its construction and the sharpness of the glass and AMAZING reticle. THANK YOU PRIMARY ARMS!!!!!!

HS503G - Watch all the videos, buy the sight, have fun!


I am fairly new to red dots. I had to go through the learning curve. I bought really cheap just see what all the fuss was about. I watched Youtube videos made by everyone. After a lot of research I finally purchased two of these. The need is there and I have a tactical shotgun that would benefit as well. I'm not after 500yrd targets, but this has made that an option to train on (I have a 1Kyd range near by). What I like best about this, so far is the quick and accurate target acquisition. I received this this weekend. After it was zero'd I just had fun. Pull up off the bench, general resting position to shooting a target was like cheating! Next purchase will be the 3x LER Gen IV is next.

A must have for any medium/short range rifle.


The holdovers work great! Rang a 12" gong at 400 yards consistently. And the auto off/on is great for range days and drill practice where youll be setting the firearm down a lot.
For the price you cant beat it. It's a fraction of the price of all the popular name brand rds' and has so many more features.

I Took a Chance

by -

Fantastic red dot. I have had ssues with some red dots over the years because of my astigmatism, and have gotten some prism scopes as a result.

I took a chance on this one hoping that the reticle design might make a difference, and I'm glad I did. This reticle design seems to have less of a negative effect with my astigmatism and I'm thrilled with this optic. Obviously, everyone's eyes are different, so YMMV.

Think I was sent a demo unit!


I just received my HS503G ACSS And have to say, I'm a little disappointed. It seems I was sent a used unit or a demo. Battery already installed in the scope, scratch on battery cover and little dusty and smudged. I'm hopefull I didn't buy a returned unit.

From PA: There shouldn't have been a return in general circulation, but we want you to be 100% happy. Contact us so we can swap it out.

Chevron not clear at all


Just received the dot for Christmas. I had high hopes for the chevron reticle , and was very disappointed. I cannot see the chevron sight at all . Looks like a dot . Even my son , with much better eyes can't see it . Don't know if I got a bad unit or what . Other than that , it seems well made .

Overall . Great optic


Was disappointed when I first got it
Chevron wasn't clear at all . Must have been the lighting indoors . Put it on and took it out to zero it and the reticle was clear , although a lot smaller than I thought it'd be . Think I'm going to get the magnifier , just not sure which one . Overall , I really like it . Was only able to take it out to 75 yards , but it's a great red dot for the money

This is the future of red dot sights.

by -

I love this sight so much I've bought THREE of them. The ACSS reticle is an absolutely brilliant idea. It's like a chevron Acog with true 1x magnification. The chevron tip is so crisp and sharp that it feels like the limit of precision is only up to your eyes or magnifier, not the sight itself -- unlike every other red dot or holo sight on the market, where the large dot gets in the way of precise shooting.

To give you an idea, I've used in the past: EOTech, Aimpoint, Meprolight RDS Pro, Trijicon MRO, etc. This optic is better than ALL of them in terms of the reticle. The only thing I'm not 100% confident about yet is durability until I stress test them personally (which takes a long time).

And the cherry on top? It's cheaper than all the other military grade optics. Time will tell if it holds up, but there is certainly nothing lacking in fit and finish vs for example an Aimpoint T2.

Mount Recommendation


I've taken it to work and absolutely loving the optic. The mount, though, came loose relatively quickly. I'm wondering what mounts people would recommend to keep the optic at the exact same height (in order to be able to continue to use my 3x magnifier).

Once I resolve the mount issue, this optic is definitely coming with me on my next deployment.