draco it all goes down to experience, Gemans were 5x more experienced than US soldiers and way better shots. If your guys live long enough they will cope with the learning curve and outshot the germans.. but i guess you'll have to play more than 2 min for that
Your soldiers are bad shot early in the game because they dont have much experience.. they get better and take decisions faster later if they survive long enough. recruits = dumb and veterants = one man army