Glock 19 MOS vs Milled stock G19

It's an issue with universal cuts for optics. It is not an issue for slides milled for a specific type of optic, when they're done well enough to support the optic properly.

Out of curiosity so I can understand your failure better, did the screws actually break off in the plate holes, or did they strip the threa
The plate screws actually broke off in the slide holes just slightly below top surface area. The screws showed no indication of being loose and i had been checking the optic from time to time to make sure everything was secure.

I'm not upset or mad, stuff breaks, i just found it interesting and reviewing the damage thought this might be a problem that afflicts univeral optic mounts in general.