Open Vs Tube Reflex Sight- A Comprehensive Guide


Reflex sights are known to be versatile and can effectively serve a variety of close quarter roles, the units tend to be limited in distance and are, therefore, limited to about 200yards if you are to take a shot while standing.

Open and tube sights can both be categorized as reflex sights and apart from the difference in structure, the open tube sight can still be categorized as a red dot sight thanks to the special reflective coating on the lens. The above then means that the illuminated red dot can only be seen by the shooter and does not go through to the other side of the lens.

So given that both the Open and tube sights are placed under one category of reflex sights, you can expect them to be accurate and faster during use. From the above it is obvious that these units have more similarities than differences, we will, therefore, break into their features and find out if there are any differences even in performance.

What are the differences between the Open and Tube Reflex Sights

Open (EOTECH 512 Holographic Weapon Sight)
Tube (Aimpoint 30mm Tube Red Dot Reflex Sight) 
Night Vision compatibility
Not Available
Night vision compatible
Water resistance
10ft (3m)
15ft (5m)
Brightness settings
12 position digital push button
Objective lens Diameter
Aiming Dot size
Battery Power
2,500 at normal setting
50,000hrs of constant operation

Open vs. Tube Reflex sight- How do they compare?

  • Brightness settings

The many brightness level settings incorporated in the reflex sights are to assist with precision and dot profile. And one thing that has theoretically remained unchallenged over the years is the fact that you tend to achieve a sharper dot profile and precision by using the dimmest possible setting. So the fact that you have various brightness settings does not necessarily mean that you will be able to achieve precision with the brightest setting.

On the contrary, if you use the brightest setting, you will notice that the dot becomes distracting and consequently appear larger on the target. Environmental conditions vary and there are, therefore, people who prefer to hunt in low light conditions, which then necessitates the use of white light, which works well with the brightest settings to enable you to see the dot after activation.

The Open reflex sight is, therefore, the better option as it has incorporated up to 20 brightness settings, and the highest can be perfect for use in low light conditions.

  • Weight

Hitting a target accurately whether in the ranges or during hunting is highly dependent on the type of sight that you are using but then there is the question of the extra weight that most sights seem to add to either the handgun or rifle and which most shooters don’t appreciate. So a sight that is highly functional and has shed off some pounds is a welcome option.

The Aimpoint 30mm tube, therefore, takes the win as regards weight because, at 225g, the unit is night vision compatible with unlimited eye relief. Eotech open reflex sight weighs up to 325g but cannot be used with the night equipment, so the extra weight that it exerts on the shooting equipment is not worth it. However, it does stack up as a good recreational and personal defense sight; the above groups are not too conscious about the extra weight.

  • Objective lens diameter

The relevance of the objective lens is to enable you to achieve precision, by gathering enough light from the front part of the scope. So naturally, a small objective lens will not gather as much light which then means that a sight with a larger objective lens will admit more light into the scope thus expose you to clear and high-resolution images.

In our case, therefore, the Open reflex sight has a small diameter objective lens at 0.85 inches, while the Tube reflex sight, the Aimpoint 30mm tube has a slightly larger objective lens diameter at 0.98in, which then makes it the best unit when it comes to the provision of high-quality clear images.

  • Water resistance and submersion

Well, both of these sights are water-resistant with a slight difference in how deep you can go with it into the water. The open reflex sight can function effectively in waters that are up to 3m deep, and if you need to go further than that either, 4 or 5m into the water, then the tube reflex sight will suffice.

So while both of these units can rarely qualify for professional use that would call for up to 25m of submersion while performing exceptionally well despite the various temperature changes, the Tube reflex can well suffice when used for sport shooting, or hunting and still offer the best performance even after being submerged to about 5m deep.

Open vs Tube Reflex Sight – A comparison Overview

Open Reflex Sight (EOTECH 512 Holographic Weapon Sight)

Aimpoint H30S 30mm Tube Red Dot Reflex Sight Standard Length with Rings - 2 MOA - 12690
  • Adjustment turret caps are the only tools required to zero the sight
  • Multi-coated 35mm objective lens
  • Unaffected by extreme weather conditions

Operating the Open Reflex Sight has to be one of the easiest thing that you will ever do because apart from the perfect orientation of the brightness adjustment buttons, you get multiple settings which you can tweak to complement your environment and consequently achieve a clear dot thus the perfect shot.

The Eotech 512 also stands out with its ability to still afford precision even in the harshest of environments, the unit will, therefore, provide you with pinpoint precision when obscured by either snow or mud, meaning it is a good unit to use in hostile and dynamic environments.


  • The sight enables easy target acquisition
  • Comes with an In-built mount
  • The sight is fairly priced


  • The sight is not night vision compatible

View Price on Amazon

The Tube Reflex sight

EOTECH 512 Holographic Sight
  • EOTECH 512.A65 - Holographic Sight in Black with 68 MOA ring & 1 MOA dot reticle
  • Mount - Compatible with both 1" Weaver and MIL-STD 1913 Rails
  • Adjustable Brightness - The 512 has 20 brightness settings for use in any lighting scenario
  • Water Resistant - The 512 is water resistant to 10 feet (3m)

The best thing about the Aimpoint 30mm tube reflex sight is that you can achieve precision with both eyes open, the unit is also highly effective thanks to the advanced objective lens system that enables better light transmission complete with unmatched optical clarity. And apart from the large 2MOA dot that will enable you to cover up to 2 inches of your target at 100 yards, you will get up to 50,000hrs of battery power with consistent use.

The rugged outer body is waterproof with a submersion tolerance of up 5m and can withstand shock and vibration.


  • Offers unlimited eye relief
  • Offers a longer battery life of up to 5 years
  • Incorporated up to 12 daylight settings


  • Brightness dials have been set on the top part of the sight, which is a bit uncomfortable

View Price on Amazon


If you want a reflex sight with minimal restrictions during use then the Aimpoint 30mm tube reflex sight is your unit, but if you want a fairly priced sight with easy-to-use features, best for recreation and hunting activities then the Open Eotech 512 reflex sight is your unit.

Final Verdict: So which is better between the Open or Tube Reflex Sight?

The Tube reflex sight is the better unit because it is night vision compatible weighs less and can be submerged to up to 5m deep into the water.


  1. How accurate is my Eotech 512 open reflex sight?

Well the Eotech 512 can afford you up to 200-300 yards but don’t expect precision

  1. Why is the Aimpoint 30mm tube reflex sight expensive?

Aimpoint equipment tend to be expensive because they are also adopted for use by law enforcement professionals.

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Terrence Miller
Terrence Miller is a hunter by birth, picking it up from a lineage of hunters and will probably hand the skill down to his son. He has been hunting since he was a young boy and has knowledge of both the new and old hunting equipment. This goes to say that the information provided is very reliable and conclusive. Using the hunting rifles and getting the right hunting gear seems to be a challenge for many individuals who want to learn the skill of hunting. And the reason why the information presented by Miller has detailed coverage on the different types of rifles, and rifle scopes. When not in the wild hunting, Miller loves horseback riding.


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