{"id":145188,"date":"2021-09-29T07:00:53","date_gmt":"2021-09-29T13:00:53","guid":{"rendered":"https:\/\/gunmagwarehouse.com\/blog\/?p=145188"},"modified":"2026-01-06T13:26:47","modified_gmt":"2026-01-06T19:26:47","slug":"open-vs-enclosed-red-dot-optics-whats-the-deal","status":"publish","type":"post","link":"https:\/\/gunmagwarehouse.com\/blog\/open-vs-enclosed-red-dot-optics-whats-the-deal\/","title":{"rendered":"Open Vs. Enclosed Red Dot Optics \u2014 What’s the Deal?"},"content":{"rendered":"

Let\u2019s talk red dots. Specifically, let’s talk about the differences between an open and enclosed red dot optic<\/a>. Red dot optics come in lots of configurations and designs with various colors, reticles, and designs that range from tubular to square, and most importantly, today, we are talking open and enclosed optics. We\u2019ll cover the benefits of each design as well as the downsides and where they fit most appropriately in the world of defensive, duty, and competitive firearms.<\/p>\n

Open Vs. Enclosed Optics<\/h2>\n

Let\u2019s define open and enclosed optics before we dive too deep into the subject. Open optics in the world of red dots refer to the lack of a hood over the emitter. These are most popular with handguns. Optics like the Holosun 507C<\/a>, the Sig ROMEO1PRO<\/a>, and Trijicon RMR all have open emitters.<\/p>\n

\"Sig
Sig Sauer AXG with Romeo1Pro red dot sight.<\/figcaption><\/figure>\n

Open emitter optics are not just dedicated to handgun optics, but some rifle optics feature an open emitter. Notably, the Holosun HS510C sports an open design and is intended for long guns.<\/p>\n

Enclosed optics feature an enclosed emitter that utilizes a hood-like system and an additional lens. This protects the emitter and ensures nothing can come between your lens and emitter. The closed emitters are more common with rifles, and optics like the Holosun 512C<\/a>, AEMs<\/a>, Sig Romeo5, and Aimpoint series all use enclosed emitters.<\/p>\n

\"Holosun
Enclosed optics mean bigger optics.<\/figcaption><\/figure>\n

Enclosed optics might be more popular with long guns, but pistol-sized optics exist. The Holosun 509T<\/a>, Aimpoint ACRO, and Sig ROMEO2 all utilize some form of the enclosed emitter. These ultra-small optics can be readily and reliably used on long guns.<\/p>\n

Today we will be using a variety of optics to compare and contrast the benefits and downsides of enclosed and open optics. I\u2019ll be using the Holosun HS510C, a long gun-oriented red dot optic that utilizes an open emitter. Besides it, I will use the Holosun 507C as a mini red dot with an open emitter.<\/p>\n

\"Benelli
The perfect shotgun and the perfect optic.<\/figcaption><\/figure>\n

For enclosed red dot optics, we will compare the HS512C and the Holosun 509T. The 512C is a long gun optic, and the 509T is a micro-sized optic.<\/p>\n

Benefits of an Open Optic<\/h2>\n

Let\u2019s talk about the main benefits an open emitter optic offers over an enclosed optic. The lack of a hood and second piece of glass cuts weight a fair bit between open and enclosed optics. For example, the HS510C is approximately ten percent lighter than the 512C. For rifle optics, this isn\u2019t a big deal but notable.<\/p>\n

On handguns, no one wants a boat anchor as a weapon. The difference in weight between the 507C and the 509T is .22 ounces. That\u2019s not much, but it does provide a clear difference between the optics.<\/p>\n

\"Holosun
Open is light and easy.<\/figcaption><\/figure>\n

As you\u2019d imagine, the open optics are smaller in general than the enclosed optics. The dimensional differences are few, but a smaller optic tends to be a less obtrusive optic. The lack of a hood and a second lens does provide some benefits worth noting.<\/p>\n

First, the lack of a hood does help open up your peripheral vision a slight bit. With rifles, it can be easier to get a compromised view through the optic in awkward situations. This can be slightly more appealing when you are shooting from awkward positions behind cover.<\/p>\n

\"Shooting
The 510C works well on lots of guns.<\/figcaption><\/figure>\n

Open emitter optics also grant you a clearer overall view. The lack of a second lens helps keep things nice and clear. A single lens provides less distortion, and it\u2019s a nice clear view through optics like the HS510C.<\/p>\n

Finally, a lot of open optics tend to be cheaper than enclosed optics. For example, the Trijicon RMR is cheaper than the Aimpoint Acro series, but both are duty-grade optics.<\/p>\n

Benefits of an Enclosed Optic<\/h2>\n

Red dot optics work via an emitter casting a red dot onto the lens in front of it. It\u2019s very simple, and all you really need is a single lens. However, with a hood and second lens, anything that gets between the emitter and the lens can cause the optic to fail and eliminate your reticle from appearing on the lens.<\/p>\n

\"Holosun
Enclosed emitter red dot optics offer higher levels of reliability than other pistol-sized red dots.<\/figcaption><\/figure>\n

This could be rain, dust, snow, and whatever else you might run into in the big wide world of unpredictable environments. A drop of rain on the emitter can cause your reticle to spatter and starburst. With no reticle, an optic is quite useless. With an enclosed optic, this is not an issue at all.<\/p>\n

The emitter remains protected by the hood and second lens. This level of protection ensures the highest level of reliability. Nothing can stop you, and you shoot in the rain, snow, and sleet without complaint.<\/p>\n

That\u2019s one of the few benefits of this design, but it\u2019s remarkably important for duty use and when loves are on the line.<\/p>\n

\"Holosun
Enclosed increases reliability.<\/figcaption><\/figure>\n

That\u2019s the most significant benefit, but the enclosed pistol optic does offer one advantage over opened. The enclosed design forces you to look through the optic and allows you to find the dot a bit easier. It\u2019s a minor advantage and really only applies to new pistol red dot shooters. Once you figure out proper presentation, then the enclosed optic does offer that advantage.<\/p>\n

Which for What?<\/h2>\n

When choosing an optic, you have to consider a few things.<\/p>\n