I have a armalite/eagle arms upper with a carry handle (made by them also) that will not properly zero (sight post has to be screwed most of the way out of base) with the standard front sight post.  I know that colt uses taller front sight towers for the A4 type uppers, but I thought they were the only ones doing this.  I was wondering it my rail is out of spec, or if armalite has started making their carry handles to colt specs.  Does anyone know what the proper rail height is for a flattop upper?