I have all flat top uppers with Rock River one piece mounts. Burris PEPR mounts are nice, but the RRA mounts are just as good, and about half the price. You can't be in a hurry with RRA though. the last mount I ordered from them took a looong time to get. Maybe not so bad now that the "big panic" is over...
Carry handle uppers are a hard sell unless you are into vintage military rifles. I think the military has even gone to the flat tops these days.
