Figured I'd start a thread to help folks with properly setting up their factory Glock MOS pistols with a Trijicon RMR. This may be of value to MOS shooters who are running other brand RDS like the Leupold DPP, but these suggestions are specific to mounting a Trijicon RMR onto the MOS system....
I strongly believe that the instructions included with the MOS are lacking in important info which could help MOS user avoid the commonly reported issues with the MOS platform. Glock does not list any specific torque values in the manual, and only specifies "Hand tight ONLY". Considering there is thousands, possibly tens of thousands of MOS Glocks in circulation currently, its safe to say that you're going to get a huge variation in what "Hand tight ONLY" means to everyone out there installing optics on these guns.
The other issue is that Glock specifies referring to the optic sight manufacturer's suggestions on which screws to use for a RDS mounting on the MOS platform. Thats not gonna work out for everyone because I don't think any specific RDS manufacturer states exactly which screws are required for proper installation of their sight onto the MOS platform. For example, If you buy a Trijicon RMR there are two mounting screws included in the box with the RMR. These are the incorrect screws to use for mounting the RMR on the MOS. They are too long and will cause a impingement issue with the MOS adapter plate and the slide. Trijicon does sell a completely separate sealing plate kit with the proper length screws for mounting an RMR onto the MOS, but its not specified anywhere in the Glock MOS instruction manual or in the Trijicon manual.
*Don't use Red or Blue Loctite brand thread adhesive. (*Blue isn't strong enough and Red Loctite is too strong and will result in stripped out screw heads)
*Only use VibraTite brand VC-3 thread sealant.
*Degrease the threads of the screws before applying the VibraTite VC-3
*Let the VibraTite VC-3 dry for at least 45mins before installing the screws.
*Get a torque wrench and install both the adapter plate and the RMR screws with 14-15 INCH lbs of torque. I've use the inexpensive Wheeler Fat Wrench without any issues.
*Do NOT use the two mounting screws that come included in the box with the Trjicon RMR for mounting on an MOS. Order the proper length screws for your desired RDS. BattleWerx.com sells RDS and MOS adapter plate screws for every RDS combination you can think of. If you are mounting a Trijicon RMR you can just purchase the Trijicon brand AC32064 "RMR Mounting Kit Fort Glock MOS" which includes the proper length screws.
*I've had none of the reported issues with a few MOS Glocks using this method over the past 3 years with over 12,000 rounds on three separate MOS pistols (Gen4 G17 MOS, Gen5 G34 MOS, and my new Gen5 G19 MOS/FS).
*I'm currently experimenting with the C&H Precision MOS adapter plates on my MOS Glocks. Too soon to recommend it yet as I only have around 1,000 rounds on it at this point, but It appears to be a superior adapter plate for the MOS platform as it supports the Trijicon RMR front & rear instead of just relying on the recoil lugs and the two mounting screws. The C&H plate also completely covers the bottom of the RMR's footprint.
*Im gonna do an RMR install on a co-workers new Gen5 G19 MOS/FS tonight and I'll make a video to post here to hopefully help out.