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How to Zero a Handgun Red Dot Sight

Red dot sights for pistols are gaining in popularity and are still a controversial topic in the firearms community. Primarily, are the benefits or a red dot worth the drawbacks of optics failure? These exact same debates arose during the early days of red dot sights on rifles, but as reliability and quality increased, those concerns quickly diminished as optics became king on rifles. In my opinion, we are at that point concerning red dots on pistols. Red dots mounted on handguns provide substantial improvements in speed and accuracy.

But just like a rifle optic, a pistol red dot sight must be sighted in, or “zeroed.”

How do you zero a red sight?

At its core, how to sight in a pistol red dot sight, or zero a pistol red dot sight, is mostly the same as zeroing a rifle red dot or rifle variable optic. One of the differences from rifle red dots to pistol red dots is shooters must first determine the pistol’s point of aim. Shoot groups at different distances with your pistol to figure out what distance your pistol sights are zeroed at, probably somewhere around 15 or 20 yards. It’s a good idea to do at minimum a five shot group, and possibly even several shot groupings, just to eliminate human error as much as possible. Just like when sighting in a rifle, use a rest to maintain consistency and accuracy.

Next, use the red dot’s dials to adjust your pistol’s red dot so it matches up with your pistol’s iron sights, just a little bit above the front sight post. (This is one of the multiple reasons why co-witnessed irons are good to have on red dot mounted handguns) Shoot the five shot group again at the distance your pistol iron sights are at to verify zero. As the saying goes, measure twice, cut once. It’s always better to over verify a red dot zero than under verify a red dot zero.

If your pistol sights are at the distance you want your pistol zeroed, great, pack up and go home. Generally, a good pistol sight in distance is 25 yards, although that may be different based on personal preference and use case. If you wish to have a different zero, shoot your pistol as is at that distance to see what difference the point of impact is, you might not even need to adjust. The point of impact shift is very minimal from 5 to 20 ish yards, depending on your ammo.

Pay special attention to focusing on the target, not the red dot.

Watch out for different points of impact with different ammo, whic is no different than a rifle. Given pistol distances and the accuracy of off hand shooting, this likely will be an imperceptible factor, but worth considering. If the red dot is mounted on a carry gun, definitely sight the pistol to the ammunition you carry, not your cheap training ammunition.

Be sure to spend a lot of time behind the gun with the red dot before carrying it for self defense. If this is your first time using a red dot mounted pistol, there really is a learning curve to the optic. Mounting a red dot to a handgun for the first time makes you a worse shooter so you can become a better shooter. The greatest learning curve with red dot mounted handguns is the initial sight acquisition. The key to overcoming this hurdle is lots and lots of draws from the holster. Evetnaully that sight acquisition will become second nature, just like when learning iron sights on a pistol.

Trijicon RMR Red Dot

What is the Trijicon RMR?

Trijicon is a battle tested company known for their high quality, highly durable firearm optics. Most known for their ACOG used by the US Military, they have many other products. One of their newer products that’s quickly growing in popularity is their Trijicon RMR, or the “Ruggedized Miniature Reflex.” It’s a red dot sight specifically designed for pistols.

Pistol red dot sights require a special mounting platform on the pistol slide. For some brands it requires custom gunsmithing, but more and more pistols these days are releasing variants that include a red dot mounting plate.

The Trijicon RMR comes in three variations, the Adjustable LED, Dual-Illuminated, and LED. Each variation comes with several red dot sizes, and the Dual-Illuminated even has a triangle dot.

Trijicon RMR Battery Life

The LED and Adjustable LED have a constant on battery life of 2-4 years, meaning you don’t have to fiddle with an on switch should the RMR be put on a self defense pistol. The Dual-Illuminated uses Trijicon’s legendary Fiber+Tritium combination. Meaning, the cable uses fiber to illuminate the dot via sunlight, and a glowing Tritium to light the dot when external light is limited or not available.

Trijicon RMR Official Page

What red dot do you put on your handgun?

Brian Purkiss
Written by

Brian Purkiss is a Christian, husband, competitive shooter, firearms instructor, proponent for individual liberty and Second Amendment rights, and a web developer. He primarily focues on USPSA and Run & Gun competitions, but enjoys most other forms of shooting competitions as well.

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Categories: Firearm Accessories, Shooting Technique, Vault | Tags: , , ,

6 responses to “How to Zero a Handgun Red Dot Sight”

  1. Allen Leaird says:

    Great vid and I appreciate the only clear explanation to a real world zeroing in process. You need your own channel.
    Just got the Vortex Venom 3 moa red dot on a Glock 19 Gen 4 I just had milled.
    Will be taking it out for a test run tomorrow. Have supressor sights ordered and will install later for co-witness.
    Life time shooter but my first venture in the red dot pistol arena.
    Thanks again.

    • Thanks for the vote of confidence! Right now I’m working hard at getting a gun shop up and running, but will be starting up my own firearm’s focused channel later this year.

      Hope your like your Vortex Venom! It’s a great pistol red dot from a great company.

  2. I have a GEN 4 Glock 19 , I had the slide milled for a vortex Viper 6MOA with black rear and white front night sights by Ameriglow and I am having trouble zero wing the vortex Viper. Mostly because the Viper does not have clicks like other or Red dot sites do, FYI the company that did my slide work was Mapleleaf out of Texas he does amazing work, in case you guys were curious!?? I cannot seem to zero because I am not 100% sure the vipers windage clicks and what they are equivalent to!?? I am also having trouble mounting it because the screw threads are different… I was wondering if anybody could help me with this issue? So basically I need to know how to mount it correctly should I use Loctite? Because the locking screws or behind the rear site, which is really dumb I thought about drilling two small holes in the rear site but I think I wouldn’t mess it up. How do I zero mount and co-witness… These are the issues I really need help with so if anyone has suggestions please let me know. Thanks in advance, and as always God bless and safe shooting

  3. Jonah says:

    Trijicon RMR on a Glock 19 gen. 4.

  4. Jim Shelton says:

    enjoyed your video. very easy to follow and apply. I have a new Trijicon rmr slide milled onto a M 34 Glock. The milling company mounted and sight centered the new dot sight. For the first test it appears to be very close @ 25 yds. I did adjust windage slightly right but will test it again before my first match. I have had extensive experience with a Burris fast fire II on my 1911 and hope the new set up will serve me as well as that set up has.

  5. Ray Bowers says:

    very helpful I was having a tough time trying to get my group like open sights thanks for the help

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