My buns/bread don't brown from top? I have tried making buns and pizza muffins using all purpose flour (bleached/unbleached/bread flour are not available in my country)multiple times at 180-200C in the middle rack of my oven. They never brown from top. I have tried applying butter on top and even doing a milk wash.please suggest what to do?
Egg wash is an answer. 

Source: http://www.dutchovendave.com/breadbasics.html

[For a shiny crust, brush the top of the bread with an equal solution of whole egg, water and milk. If desired, sprinkle with poppy, caraway or sesame seed or rolled oats.  For a softer, deep golden brown crust, brush with softened butter or margarine.  For a crisp crust, brush or spray lightly with water.  For a soft, tender crust, brush with milk.  After glazing (brushing with one of these ingredients), slash the top of the loaf with a sharp serrated knife, cutting about 1/4 inch deep, once down the center of the loaf or across the loaf a few times.]