Continuing with the discussions on how to optimize and enhance the reliability and utility of your red dot pistol sight I will be addressing three points in this article. The issue of rain on the RMR lens, the issues sometimes encountered with electrical conductivity (specially with older RMRs and batteries with less power..ie., older batteries), and the issues with zero adjustment dials that are loose.
First the rain. Here in Arizona it rains hard. Hard like downpours of Monsoon Proportions. Will the lens of the RMR become occluded? The answer is - Of course it will. Just like your eyeglasses, binoculars, or the lens of your rifle scope. This will be a greater issue if you carry openly rather than in a concealed manner. In one of our summer training sessions, we were drenched with a refreshing but brief monsoon. The TSD RMR-equipped Glock was protected by clothing and the red dot quite visible and usable.
If open carried, such as in a tactical drop leg holster, the water may pool in the shooter's side area of the lens and collect were the red diode is housed. This will make the sight picture blurry, and you will see refraction errors. Guys who experience this get flustered with the inability to use the red dot as usual, but let me put this in perspective.
If you have this situation happen, and need to draw and shoot a threat right there inside of 7 yards, you do not need to use a traditional sight picture at all. That some ostensibly experienced and prolific trainers are still, at this day and age, pushing the "all sights all the time" mantra is as astounding as a grown man still thinking the earth is flat.
To prove it to yourself you needn't come to one of my classes. You can simply tape over the entire red dot sight with masking tape and go through your usual drills at zero to ten yards, relying on body index and your habituated and uniform grip and shooting position. Yes grasshopper, you can hit COM on a steel target while visually focusing on the threat and not on the sights.
Of course, if there is time for shots beyond the close range reactive envelope, a simple clearing of the water is possible and a wiping of the glass...just like you'd do with the Aimpoint on your M4. As well, understand that in a downpour, using any sights will be difficult, and seeing a target past close quarters environments will be difficult as well.
One other thing that can be done for light moisture concerns is the use of Rain-X. This will help the water run off the glass. Its not an anti-rain product, just one that tends to keep the glass on scopes, eye glasses, and optics clear in moist environments. Is the use of optics in the rain difficult? Sure...but its not the end of the world that some guys say it is.
Next, conductivity. The weak link in anything battery powered is the battery. When guys ask what to do when their RMR shuts off, I tell them the first thing to do is replace the battery. Incidentally, if you are properly co-zeroed with the irons, there is no re-zeroing necessary as the dot can be verified to be in the same spot on the irons.
Continuing. Sometimes that "new" battery will have been sitting on the drugstore or hardware store shelf for months. I am not sure if batteries have a sell by date, but they probably should. Nonetheless, in addition to using truly "new" batteries, I was told of a possible "fix" to get the most from the existing battery. That is the use of conductivity grease on the battery contact during installation.
Conductive grease, or electrical contact grease products have been on the market for years and have been used on various electrical units ranging from bicycles to motor vehicles. One alternative quick fix is simply petroleum jelly. These products provide antistatic conductivity, provide moisture protection, heat protection, and are effective at extremes of low to high temperatures. Used in conjunction with the insulator plate we include in our installations, it should make the red dot system work even better. I plan on conducting some tests to see how well this works.
Last, the loose zero adjustment dials. In all honesty, most of the loose zero adjustment dial issues I have seen can be attributed to third world adjustment methods. But there have been a handful that have been sent back to Trijicon for repair due to dials not being sufficiently robust. One easy fix is to use RTV, or Room Temperature Vulcanizing to cover the screws once the zeroing process is complete. This is similar to old "nail polish" on the scope screws we learned in sniper school, except that this is rubber, and will seal the entire screw surface. Unlike the nail polish, it can be peeled off with some effort if a rezeroing of the RMR is needed when moving the unit to a different pistol.