I finally received the Holosun 507C this AM after Fedex sent it on a 3 hour tour of the US.
Anyway, I am attempting to mount it on a Brownell's Glock slide cut for the RMR footprint. The trouble is, the 507 doesn't quite fit flush on the slide. It rides on top of the slide mounting studs. I can see daylight between the slide and the 507. The 507 rocks on the studs.
The mounting holes on the 507 appear to be bored uniformly. Why the studs aren't going all the way through the 507 is beyond me.
The Brownell's slide appears to be properly built.
I am genuinely puzzled.