I have an Eotech 552 on my DPMS 7.62x51 and a 4-12X50 on my Rock River Arms M4. The Holoscope fits on my flat top, and I have a riser on my M4 with its flat top. You have to take off the Tactical carry handle. The sights don't fit.
With a see thru riser you can use the tunnel and the front sight post in a close in situation.
I would have no qualms about swapping out the optics between these rifles, same application.