I mentioned earlier in this thread that I am trying to put together an A2 style rifle at the current time. This is proving to be much harder than I expected. I went to a large gun show this weekend (the Nation's Gun Show in Chantilly, Virginia), and all the complete uppers -- and even stripped upper receivers -- that were for sale were of the flat top variety. Brownells has a stripped A2 upper (DPMS), but the only suitable barrel assembly that they carry (without the M4 ramps) has the "F" marked front sight base. (The "F" marked base is slightly taller, so that it co-witnesses with a clamp-on carrying handle on a flat top receiver.) Not only that, but this barrel has the "government profile" with the thinner section under the handguards. And these components are not cheap, by the time you add them all up.