It may seem as though I am including far too many pictures of firing embrasures, but they're just so cool, you'll have to forgive me. The curving band of iron directly in front of the embrasure is one of two, upon which the equally iron wheels on the gun's carriage would run, to make for ease of aim. And by "ease," I mean several guys straining to manhandle several thousand pounds of blisteringly hot iron into position for each shot while the gunner yelled at them to hurry up.