And, just like last week... Mounting the optic on the carry handle is a mistake for most but not all people, for several reasons including the following:
1. The cheek weld or lack thereof, is too high. That is, unless you have facial features that closely resemble Jay Leno or John Kerry and enjoy your chin being your anchor point.
2. The use of a carry handle mount doesn't allow for co-witnessing in any desirable form.
3. The use of the iron sights for back up purposes is greatly diminished (if not eliminated) even if the mount has some "tunnel" for using them.
Some people like them but they are very few and very far between. Do as you please but it is really a poor choice when one considers the low cost of flat-top uppers these days. Furthermore, one could sell there A2 or A1 upper, if they choose, and almsot break even on the flat-top upper purchase.