How tall does the KAC RAS picatinny adapter for the MP5 sit in comparison to say the OEM Zenith, MFI low, etc?

What keeps the rail from flexing downwards into the top of the gun?

Edit: I am inquiring about the optic mount for the MP5 RAS rail.

Not sure how tall the pic mount ones are, but the HK RAS rails have a hinge similar to the RAS/RIS rails on the M4 that tightens up on the receiver that prevents movement.

I'll get some photos for you.

Sorry for the confusion, I’m asking about the optic mount for the MP5 RAS.

The front mounting points are so strong that you'd have to put devastating force on the mount to get it to flex.

To answer my own questions after receiving the item:

It IS taller than the MFI/HK Parts ultra low profile mount. The KAC picatinny adapter puts my previously lower 1/3 cotwitness on a low weaver 30mm mount + Aimpoint ACO above the irons. Ultimately loses the ability to cowitness irons with the optic.

There is nothing preventing the aft of the picatinny section to flex downwards towards the receiver upon impact. There is roughly 0.145” of a gap between the underside of the picatinny rail and the top tube of the receiver.