I have pretty long legs and a chair with any lean at all makes a 4' deep shooting house plain miserable for me, not to mention if I have to turn hard to make a shot out of a side window I have to nearly stand up to keep my knees and feet from getting caught on a 2x4 or rubbing the front wall. I build mine 5' deep and 6' wide. I have a couple that are larger, but 5x6 is as small as I want to go.