...I'd look at replacing your upper with a flat-top before looking at glass.
+1 And I picked mine up at walmart off 26 in Laffayette.We just got in one of the Nikon P223 Carbine 3x scopes which would probably work well on a carry handle. They run $159.95.
That said, mounting any optic on top of a carry handle isn't the best solution. I'd look at replacing your upper with a flat-top before looking at glass.