This smaller screw was one of two which came with the red dot, and after five shots let loose and sent the RMR into my forehead. The replacement screws from Primary Machine seem larger and definitely gave more feedback threading in just now.

Did the factory include the wrong diameter screws, or is the factory Glock mounting plate drilled and tapped larger than what Trijicon had intended for their product?
Attached File

Belay that, I missed a key point.

I know Glock had an issue with the first MOS plate screws, however I’m not sure if they are a different thread pitch. I remember the Flying RMR saga at a RYG match shortly after the MOS came out. Screws were too short and launching red dots everywhere halfway through a plate rack run.

The Primary Machine ones felt much, MUCH nicer being threaded in. The thread pitch is different and the diameter of the screws are different as well.

The screw on the left appears to be a 3mm screw like what is used to attach to a MOS plate to a slide, while the right screw looks to be #6-32, like trijicon specs to mount the optic.

I think you used the wrong screws if it was mounted on an MOS glock and you used the factory screws...

The screws to mount the plate to the slide and the screws to mount the optic to the plate are NOT interchangeable. The thread pitch and the size are different.

I went through this when I first got a dot. Neither the RMR, nor the Glock came with the right screws. There was one set that was far too long, and one that only had like a thread or two of engagement. I said, fuckit, the manufacturer must have a reason for that, and used the short ones.

Wham, right in the forehead. Big lump. I should have known better.

So, I looked to the aftermarket…Glockstore, I think. The screws they sent were too large in thread diameter. So, I contacted them, sent pics, and discussed the problem. They sent me new screws, and said they tested them before sending to ensure they were right. Nope. Not even close.

I ended up using CHPWS, and have used their plate and screws on every Glock since.