Green Mountain barrels are harder to draw file than some others, but the end result is the same. Hold the file's handle in your left hand, and pull (draw) it toward you to cut. I do half a flat at a time, then reverse the barrel and do the other half of that flat. I hold the barrel in a piece of thick, clean leather, and never touch the barrel again, with bare fingers, until after it is browned. So the rifle is practically finished by this stage.