Guides Handguns

Pistol Mounted Red Dot Sight Failures and How to Deal with Them

One of the things I've noticed after talking with folks about pistol mounted red dot sights, is that not everyone is aware of types of failures that may occur with an RDS and how to deal with them. Spoiler: back up sights aren't necessarily the answer. Let's explore front sight obstructions, rear sight obstructions, and complete RDS failures.

It’s no secret. I jumped on the pistol mounted RDS bandwagon over a year ago and haven’t looked back. What can I say? I’m a fan and firmly believe RDS sights on pistols will become the rule rather than the exception as they continue to grow in popularity. In my opinion, they are the way of the future and the future is now.

Over this past year, I’ve learned a lot about RDS sights as a result of using the VP9 with a slide mounted RMR in practice and at a few training courses – including one training course specifically tailored towards usage of pistol mounted RDS. At the same time, I’ve conversed with several folks who are interested in giving a pistol mounted RDS a go or just got started with one. These discussions have covered a wide range of topics with the most common being eye focus, presentation of the firearm, and back up sights (I expect to cover some of these topics in future posts). However, I want to focus on a topic that is less frequent, but incredibly important. In my opinion, significantly more important than back up sight selection. That topic is, as one may have guessed from the title of this post, RDS failures.

Anyone one serious about pistol shooting, whether it’s for defensive or competitive purposes, will spend some time running malfunction clearing drills. These are important drills to practice as these malfunctions create a bang stoppage. As such, the drills focus on clearing the malfunction and getting back on target and on the trigger as quickly as possible. But that’s not what this post is about. I only mention these because these drills ingrain the habit of fixing a problem when the shooting cycle is disrupted. RDS failures are similar in the sense that they can disrupt the flow albeit not mechanically and that means that we, as shooters, have to add a new habit to our get back in the flow toolbox.

RDS failures fall into three categories: 1) front side obstruction, 2) rear side obstruction, and 3) complete RDS failure. Let’s explore these.

Front Side Obstruction

The front obstruction failure occurs when something blocks the front side of the RDS. The obstruction could be mud, dirt, a bodily fluid, or anything else that obstructs the field of view. We can simulate this failure by placing masking tape on the front side of the RDS and training with it.

The interesting thing about this “failure” is that we shouldn’t notice that it occurred assuming we maintain both of our eyes focused on the target. When the front side of the RDS is obstructed, the dot produced by the LED is still reflected off the RDS and is visible to our eyes. Even though we can’t see through the RDS our brain does it’s thing using the visual data collected from both eyes and fills in the blank. That means we should be able to clearly see the full target with the dot on it as if the front side obstruction never happened.

If we do notice the obstruction, that’s an indication that we are focused on the dot and likely holding on to the front sight focus habit most pistoleros have developed. Noticing the obstruction may interrupt our flow since we don’t have a clear sight picture to work with. The flow interruption could trigger the clear malfunction quickly and get back to work habit that is also ingrained in most of us. However, it’s important to remember the pistol isn’t mechanically blocked from going bang. So the corrective action is to refocus on the target, let the brain magic kick in, and get back to work.

Something to try to develop the target focus habit and break the front sight focus habit is to place masking tape on the front of the RDS for the entire duration of one (or more) dry practice or live fire session(s). Do this enough and flow disruption from front side obstructions will likely cease to be a thing.

An important thing to note is that a front side obstruction will render back up sights useless since we will be unable to see the front sight.

Rear Side Obstruction

As the name implies, a rear side obstruction is an obstruction of the back side of the RDS. Like a front side obstruction, the obstructing material is irrelevant. Also like a front side obstruction, a rear side obstruction usually renders back up sights useless. Unlike a front side obstruction, the red dot is no longer reflected back to our eyes by RDS and therefore brain magic can’t help us.

Sounds like a bad time right? The truth is rear side obstructions are more likely to disrupt flow than a front side obstruction because we lose our sighting system. While it might be tempting to stop pressing the trigger and clear the obstruction, there is guarantee the obstruction can be cleared quickly. Furthermore, the obstruction may be caused by material blocking the LED rather than the lens which can happen with RDS that are not fully enclosed. The good news is there are three different techniques that can be used to continue (or resume the flow) when a rear side obstruction occurs. They are:

  • the guillotine method – where we focus on the top side of the RDS as a point of reference and aligned with the top of the target,
  • the ghost ring method – where the frame of the RDS lens is used as a point of reference and held over the target,
  • and the backplate method – where the backplate of the pistol is used as a point of reference and aligned just under the center of the target.

These methods can be practiced by placing a bit of masking tape on the rear side of the RDS and engaging in live fire practice. To be honest, my mind was blown when I realized that an individual can still place accurate hits on target at a relatively rapid rate without the use of the dot or back up sights even at distances hovering just north of 20 yards. Granted precision suffers and the result is larger groups. However, fast accurate hits are possible as proficiency with these methods improves.

The best method depends on the RDS and the individual. I’ve found that using the guillotine method with the concave top side of the RDS works very well for me and my setup. Your mileage may vary.

Complete RDS Failure

This is the one type of failure that back up sights can usually provide value as a secondary sighting system. However, that value isn’t guaranteed.

The most common cause for a complete RDS failure is a dead battery. In this case, we are left with a clear window and back up sights can be used. At the same time, a complete failure of this nature is easily mitigated by regularly changing out the batteries on the RDS.

Another cause could be electronic component failure. In this case, back up sights can provide their full value.

The last cause I can think of as I’m writing this is a complete failure to direct physical damage. In this case, we may also have a broken front sight, a broken (or shattered) lens, electronic component failure, a front or rear side obstruction, or a combination of any of these. There is a chance that back up sights might not be usable in this situation. So what can we do? Assuming the pistol is still functional, we can treat this situation as a rear side obstruction and use the same methods to get back into the flow.

What does this all mean? It means that back up sights are a good idea (I’ll get deeper into back up sight selection in a future post). It means that we must be aware of the possible failures and develop habits that can keep us in the flow. That translates into maintaining a high level of skill with traditional pistol sights, developing shooting skills while maintaining target focus when using a functional RDS, and developing proficiency with at least one of the three methods used to overcome rear sight obstructions. That further translates into practice, more practice, and perhaps attending a training course or two.


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