I picked up some coyote brown furniture for my AR and my wife surprised me with an EOTech 552 for Christmas.  When I mount the sight on my flat top Colt, I have to move the scope to the far rear because the CavArms handguards seem to be fatter(larger diameter) than the original A2 style.  I want to get a BUIS, but right now I don't have any room to mount it.  Anyone have this configuration of furniture and scope and/or what is the best solution?

There is room for a 552 and BUIS on your upper receiver.

From the looks of it, you have similar handguards.  I'm assuming your BUIS only uses one grove on the pic rail? and that your sight is shoved all the way against the forearm.  When I do this, I do have one vacant grove behind the sight.  Who makes your BUIS?

thanks for the photo graphic evidence!