Hey all,

I was lucky enough to land myself a BNIB Daniel Defense Contract Overrun upper with the FSB and DD fixed rear sight. There's just something about these that I really love aesthetically, and I am already in the habit of building uppers with backup sights so...


My questions are:

1) Are your standard KAC or Magpul flip-up REAR sights going to match the FSB height?

2) Does your regular Eotech EXPS require a riser to be true cowitness, or does the riser create lower third?

Thanks!

1) Yes.
2) EXPS is already lower 1/3rd. XPS would be absolute.

I've never had a problem matching up various rear BUIS to a FSB.

Even if rear has no elevation adjust, the elevation adjustability in the front will easily compensate.

No experience with any Eotechs.

https://www.ar15.com/forums/AR-15/Optics-Mounts-and-Sights/18/