Not to highjack your thread ....... and hopefully a free bump for you ........... but I'm interested in seeing how this plays out for you. I too have one of these rifles. I bought mine a few years ago when I happened to walk in Columbia and they had a floor full of uppers in boxes. I had wanted an A4 w/handle clone for a long time, so I bought it on a splurge. Mine has the same problem, but my rear sight is adjusted all the way to the right (starboard when shooting). I'm not bottomed out, but I'm just a click or two from it. Also, my front sight pin is pretty high in my opinion. It's to the point that the base of the pin is all the way out of the sight base. The top of the sight pin is above the guards (ears) of the front sight base. I have it sighted in RIBZ with the small diameter aperture and Federal/LC 5.56 M855. It shoots good, as I can constantly ring 10" steel at 300yds with it ....... so I've kinda just learned to live with it, even though it bugs me. I just try to be careful not to hit the front sight pin in fear that it would bend, break, etc.
For those that are wondering, I did measure the 'F' marked front sight base and it's 1.98" and the detachable carry handle is Mil Spec at .835" (as they both should be) ........ and that's per Hornady reloading calipers.