Holosun 403 Vs 503 – The Ultimate Comparison

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Hey Shooters, Welcome to Holosun 403 Vs Holosun 503 Comparison.

Holosun is a well-known brand for pistol optics. Two of the most popular sights they offer for your pistol are the Holosun 403 and the Holosun 503.

In this Holosun 403 vs 503 comparisons, I’ll put the two sights to the test and delve into more detail about their similarities and differences. I have thoroughly analyzed them in the following categories to set them on an equal basis for a side-by-side comparison:

  • Glass Clarity and Reticle
  • Durability
  • Battery Life and Brightness
  • Parallax and Magnification
  • Size & Weight
  • Price


This specification table contains all the details about the two sights, helping you to decide which sight best meets your needs and what features each sight offers.

 Holosun 403Holosun 503
Housing MaterialAluminumAluminum
Item Dimension2.36 x 1.57 x 2.95 inches5 x 4 x 4 inches
Weight2.82 oz4.87 oz
Parallax FreeYesYes
Unlimited Eye ReliefYesYes
Reticle ColorRedRed
Reticle Options2 MOA Dot2 MOA Dot & 65 MOA Circle
Battery TypeCR2032CR2032
Battery Life5000050000
Night VisionYesYes
Power SourceBatterySolar & Battery

What’s in the box?

The following items are included in the box of Holosun 403 and 503:

  • Low Profile Mount
  • Screws
  • Lens cleaning cloth
  • CR2032 Battery
  • User Manual
  • Rubber Cover

Compare Deals:

Holosun HS403C
HOLOSUN HS403C Solar Power Micro Red Dot Sight

Compare Deals:

Holosun 503CU
Holosun HS503CU, Paralow Red Dot Sight
Holosun HS503CU Paralow Red Dot Sight 1x 20mm 65 MOA Circle with 2 MOA Dot Picatinny
Holosun HS503CU Multi-Reticle Circle Dot 20mm Micro Reflex Sight
Holosun HS503CU Red Dot Sight
Holosun HS503CU 2 MOA Circle Red Dot Sight

Comparison of Holosun 403 And Holosun 503

1. Glass Clarity and Reticle

The reticle on the 403 is a 2 MOA red dot. Although it wouldn’t be optimal for someone with astigmatism, this is standard. Glass clarity is nicer than you might anticipate on a tight budget. The lens is multi-coated, boosting clarity and light transmission, and the little red dot you want to see on your target is sharp and well-defined.

However, the reticle on 503 is a 2 MOA dot with a 65 MOA ring. For the needs of the majority of individuals, a 2 MOA is ideal because it is both big enough to be seen when aiming and small enough to be extremely precise at long range (showing a 1” dot at 100 yards). This process is made even more efficient by adding the 65 MOA ring.

When zeroing in on your target, you can use the 2 MOA dot reticle, which is quite precise. I know many shooters favor it, and I don’t see anything wrong with it. But I love the Holosun Circle Dot Reticle myself. The same 2 MOA dot is used in the middle, but a large 65 MOA outside circle surrounds it. This is the red dot sight reticle that I prefer the most! The 65 MOA outer circle’s great visibility allows me to move faster toward nearby targets. But at the same time, I have that clear 2 MOA dot in the middle, enabling me to aim precisely while shooting at far targets. I haven’t yet discovered any optic in this pricing range that offers a comparable reticle design. Therefore, this is a significant element that makes 503 stand out.


Since 503 has two reticle options, it wins in this category.

2. Durability

Both optics offer exceptional resilience when it comes to durability. The 6061-T6 aluminum used for the main body of the sights is machined from a billet and finished using a process called MAO (Micro-Arc Oxidation), akin to anodizing. This results in a hard, opaque, and scratch-resistant outer layer. As civilians, the only features we truly want in a red dot sight are shock resistance and waterproofing. It can readily withstand being wet in snow or rain. Furthermore, it will hold up well even if it falls into the water or splashes if you navigate damp terrain.



3. Battery Life and Brightness

Both of the optics require CR2032 batteries, which have a 50,000-hour lifespan. The battery life is around five years. Long battery life is something that many people value because it enables them to leave their sights on all the time. This is important because it lets you quickly grab your gun and be prepared to use it without fussing with your sight in case you need it for home defense. If you replace the battery once a year, your sight should continue functioning well even though it is always on.

Holosun features motion-sensing technology, which provides the “shake awake” feature on both models and its remarkable battery life. This implies that your sight will automatically switch off after inactivity and turn on when the optic detects any motion (for example, when you pick up your gun).

One distinction between the two optics is that the Holosun 503 uses solar power, allowing you to use it without a battery as long as sunlight is available. The reticle’s brightness will also automatically adjust to your lighting circumstances while configuring to run on solar power. This cutting-edge feature distinguishes the 503 from nearly every other red dot on the market.

Since both the 403 and 503 offer 10 Daylight Brightness settings and 2 Night Vision Compatible settings, they are both fairly adaptable. Therefore, you’ll be able to effortlessly adjust the brightness of your sight regardless of the lighting situation you find yourself in.


I believe that the 503 is the winner in terms of battery and brightness because I like that it has the solar power option. It makes things much easier. However, the remaining characteristics are the same in both optics, making them stand equally.

4. Parallax & Magnification

Both optics are identical in terms of magnification and parallax. They have a 1x magnification scope, so everything you’re looking at will be 100% larger than it was before. That won’t help much at a distance, but that isn’t what these scopes are designed for. They function similarly to reflex sights and have the advantage of being parallax-free.



5. Size & Weight

Holosun 403 is a small sight. It doesn’t appear to be all that large. The total size is 2.45×1.43×1.6 inches. As you can tell, this sight is relatively light in height and length. The mounting system may appear very tall, but it isn’t. It is at the ideal height to use the sight from a considerable distance and sits flat against the rail. The Holosun 403 weighs 2.82 oz, according to its advertising.

Moving on to Holosun 503, which is marginally larger than 403. It feels dense in the hand when holding this sight. There is some weight to it, though not quite like a brick. It seems like you are buying high-quality equipment rather than a collection of cheap plastic and pot metal. The total size is 2.6×1.43×1.6 inches, and it weighs 4.86 oz.


Due to the equal sizes of both optics, this category is a tie. The difference is hardly noticeable. You won’t even be able to tell that they are different.

6. Price

Both 403 and 503’s prices change often, but they typically don’t shift more than a few dollars, so they will be reasonably priced regardless of where you get them.

The Holosun 503 costs high, but the high price is justified because it offers more features worth the cost. Because of how well it performs, I wouldn’t mind investing a little extra money if it meant I wouldn’t compromise on durability.

The price difference between the two sights is just a few hundred dollars. For some people, this might not make much of a difference, but for others, it might completely alter their choice, so I understand if the price is a factor that’s high on your list of concerns, given the difficult times many people are going through right now.


Despite being slightly more expensive, I’d choose the 503 since it offers better reliability, shooting accuracy, and performance. If you’re a passionate shooter like me, you know that spending more money on a high-quality optic will pay you in the long run over a less expensive model that will need to be replaced after a month.


To conclude, both sights perform superbly. Both sights feature an extraordinarily clear image quality, so your lenses will not be compromised regardless of which one you choose. They are both built of aircraft-grade aluminum, providing them with waterproof and shockproof construction. Due to my preference for the Circle Dot Reticle, I prefer the Holosun 503. It’s my preferred reticle on a red dot sight. The ability to shoot swiftly with the 65 MOA ring while yet having access to the tiny 2 MOA dot for precise aiming is something I appreciate. All in all, it works incredibly well for me and is quick and precise.

Now, if you want to save some money and are content with a 2 MOA dot (which is still a fantastic reticle!), I suggest you get the more reasonably priced Holosun 403c because it’s still a fantastic sight.

Frequently Asked Questions

What is the difference between Holosun 403 and 503?

The reticle is where the two differ most significantly. While Holosun 503 includes the multi-reticle system (MRS), Holosun 403 has the traditional 2 MOA reticle. This means that the 503 users can alternate between the traditional and circular dots (i.e., a 65 MOA circle with a 2 MOA dot in the center).

What is the diameter of Holosun 503?

The Holosun 503 is a 20mm micro-optical sight suitable for rifle and carbine use.

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