Red Dot

[waho]

Whats the difference between tube type and the exposed lens type red dot sights. I'm looking for something to put on my 22 target pistol. Iron sights are getting hard to see.

[Kelster1574]

Good question, curious to hear the differences.

[OpticsPlanet]

Here are a few excerpts from a handout I made for my colleagues. There is some pretty good info here. I'm not sure if every piece applies, but here it is:

Reflex sightsFull Tube and Small Tube Red Dot sights:Open Sights and Mini Red Dots:
Open sights have a lower profile than tube sights and are not as ruggedly built. This is due to the fact that they only utilize the reflecting optical window in their design. These types of red dots typically do not accommodate caps or filters because of their low profile design. For protection and storage they often use scope coats.

Mini Red Dots
Mini Red Dots are small versions of open sights. They can be used on rifles, shotguns, and are particularly useful on pistols because of their size and lower profile. They often use various plates that will allow them to be attached to the rear sight dovetail or picatinny mounts. It is also common to see them used as a close range sight on rifles with higher magnification scopes. They are also great for skeet and trap shooting. Some pistols like the FNP-45 Tactical have integrated mount that is specifically designed for the user to attach a Trijicon RMR or Docter sight directly to the slide.

Holographic Sight
Holographic sights are more commonly associated with the EOTech sights and are sometimes referred to as an HWS. A holographic sight is different than a reflex sight in that it does not use a reflected reticle system. Instead, it projects a hologram on to the target plane. The hologram is created with a laser; therefore it will not have as long of a battery life as an LED powered sight. For example, the EOTech EXPS3-2 has a 600 hour battery life while the Aimpoint COMPM4 (LED) has an 80,000 hour batter life. However, since it uses a laser, the dot size can be infinitely small. What you see through a holographic sight is a reconstruction or projection of a reticle image.
These sights are parallax free and are 1x magnification so eye relief is not an issue. They also have a brightness control that will allow the shooter to adjust the brightness of the reticle to best suite the given lighting conditions. Some will also have a night vision mode that will automatically dim the reticle to a level that will not overwhelm the intensifier tube.

Chase B.