[German]

Note:

I haven't measured myself, so this is just research. Take it for whatever it's worth:

Does anyone have numbers on the difference in height over bore for a 416/MR556 as compared to a regular AR?

History-wise the Troy Micro BUISs were developed specifically for the HK416 to result in the same height-over-bore als with a standard AR15/M16/M4 as far as I know.

Difference in height over rail is 0.2", so difference in height over bore should be the same amount.

The Troy Industries Battle Sights have set the standard for performance and durability. Now, Troy has developed a rugged low-profile sight designed for firearms with top rails higher than the standard M4. The Troy Industries Micro Battle Sights are also a terrific option for shooters who favor a sightline that's as close to the barrel as possible, or for those with raised top rail systems, the Troy Micro Battle Sight provides an ideal solution. The Troy Micro Battle Sights are rugged, reliable and Battle Ready.

Notes:
Troy Industries makes two sights; standard and micro.

The measurement to the center of the standard aperture is 1.36”.
The measurement to the center of the micro aperture is 1.16”.

The standard sights are meant for Mil-spec top rails and the Micros are meant for the weapons such as the IAR, Robinson Armament XCR, Heckler & Koch 416 & 417, and other weapons with raised top rails.


Source

Per email directly from Troy:

Standard BUIS rear sight centerline = 1.36" above rail.
Medium BUIS rear sight centerline = 1.27" above rail.
Micro BUIS rear sight centerline = 1.16" above rail.

Source