RE: the use of Trijicon's or third party sealer plate for RMR with the OPF-G, RMR, our position is it is not necessary.
Trijicon has a section on its RMR FAQ page on this topic: https://www.trijicon.com/frequently-asked-questions/category/rmr-faqs
To clarify, we called Trijicon and spoke to one of the support representatives. On the OPF-G, RMR, the plate to slide screws are contained within the gasket, his opinion is a sealing plate is not needed. It is Trijicon's position that if a user is unsure, use the sealing plate. The thickness it adds is so tiny as to be inconsequential to the thread engagement, and we agree.
Though a sealing plate is not needed, OPF-G, RMR thickness is based on Glock's MOS plate which requires it, which makes OPF-G, RMR compatible with a sealing plate. Having a thin plate does reduce thread engagement by a tiny amount but it's so small as to be immaterial. Glock's MOS plate sight to plate engagement is adequate, no more and no less. When thread engagement is adequate, more of it isn't helpful in any linear fashion, and quickly crosses the point of diminished, or zero return.
OPF-G, RMR's design holds the RMR tightly on the plate and immobile before the sight to plate screws are installed, which minimizes the sight to plate screw's role to that of simply holding the sight down on the plate, as they are not responsible for keeping the sight from moving in recoil.
We've been fortunate to receive input, and in the field, actual use data from agencies that authorize FCD equipment, this is crucial in our effort improve and validate existing designs.
Below is from an Abilene PD armorer regarding the question of RMR sealing plates:
Below is from an Abilene PD armorer regarding the question of RMR sealing plates:
No plate required. The continuous surface of the OPF-G provides a good seal. I have seen zero water intrusion in actual field use across 35+ examples that I’ve been swapping batteries in.
It (water or moister intrusion) hasn’t been an issue in our use or tests. The proper application of the provided vibratite helps to occlude intrusion through that avenue also. I did water exposure and immersion tests with my initial plate and optic and had zero moisture intrusion.
I have since shot during at least 6 long rain days with one, and we do water/rain exposures as part of our RDS training, usually using my setup for these. That’s where we use a spray bottle to constantly spray water on the optic to replicate heavy rain/water exposure and shooting. Still, every one I’ve popped for battery change has had zero indication. For 99% of users I seriously doubt they will ever expose it to the amount of water required for the through holes to be an issue.
It (water or moister intrusion) hasn’t been an issue in our use or tests. The proper application of the provided vibratite helps to occlude intrusion through that avenue also. I did water exposure and immersion tests with my initial plate and optic and had zero moisture intrusion.
I have since shot during at least 6 long rain days with one, and we do water/rain exposures as part of our RDS training, usually using my setup for these. That’s where we use a spray bottle to constantly spray water on the optic to replicate heavy rain/water exposure and shooting. Still, every one I’ve popped for battery change has had zero indication. For 99% of users I seriously doubt they will ever expose it to the amount of water required for the through holes to be an issue.
Another story, this was shared on ar15.com https://www.ar15.com/forums/handguns/MOS-owners-get-in-here--Better-plate-system-inside-/13-188416/&page=37
Just wanted to mention this story, as some of you might find it useful.
Our agency now has about 30 RDS-equipped handguns, issued to our SWAT team and training unit. They are issued guns--G17.5 MOS with Trijicon RMRs and FCD plates, with no sealing plate. We have had them in service now for about 6 months.
A few days ago we had a call-out. One of our snipers took up a position of cover in the prone position at the edge of a dirt road. A short while after deploying it started to rain--hard. Within a few minutes he was laying prone in a puddle of moving, muddy water, with the top end/sight of the handgun submerged. After lying in the puddle for about an hour and a half the call-out was resolved. Immediately after the debrief he started cleaning up his equipment. So much water/mud/dirt had collected in the holster that the deputy had to force the hood forward to draw his handgun (he advised that he didn't believe this was a deficiency of the holster, and believed any holster would have had similar problems in that situation).
After a thorough exterior cleaning of the handgun he called me and asked if I would like to take it down to an armorer's level inspection, and to check the RMR to make sure there were no issues. I felt this was a great opportunity to check the 'weatherproofedness' of the sight and plate. I am happy to report that there was no intrusion of water/dirt/debris in between the sight and plate (remember, we are not running a sealing plate). Also, just as an aside, the operator mentioned that, while the sight had been submerged in water for over an hour and there was visible water on the sight/glass and some 'starburst,' he would have had no problems using the sight, if necessary.
Anyway, just anecdotal real-world report.
Our agency now has about 30 RDS-equipped handguns, issued to our SWAT team and training unit. They are issued guns--G17.5 MOS with Trijicon RMRs and FCD plates, with no sealing plate. We have had them in service now for about 6 months.
A few days ago we had a call-out. One of our snipers took up a position of cover in the prone position at the edge of a dirt road. A short while after deploying it started to rain--hard. Within a few minutes he was laying prone in a puddle of moving, muddy water, with the top end/sight of the handgun submerged. After lying in the puddle for about an hour and a half the call-out was resolved. Immediately after the debrief he started cleaning up his equipment. So much water/mud/dirt had collected in the holster that the deputy had to force the hood forward to draw his handgun (he advised that he didn't believe this was a deficiency of the holster, and believed any holster would have had similar problems in that situation).
After a thorough exterior cleaning of the handgun he called me and asked if I would like to take it down to an armorer's level inspection, and to check the RMR to make sure there were no issues. I felt this was a great opportunity to check the 'weatherproofedness' of the sight and plate. I am happy to report that there was no intrusion of water/dirt/debris in between the sight and plate (remember, we are not running a sealing plate). Also, just as an aside, the operator mentioned that, while the sight had been submerged in water for over an hour and there was visible water on the sight/glass and some 'starburst,' he would have had no problems using the sight, if necessary.
Anyway, just anecdotal real-world report.