Lowell, you're having linguistic challenges again. "Field Grade" has to do with a lack of engraving, less than XXX walnut, less than the finest checkering--in other words, a working gun. "Field gun" is any gun you take afield, regardless of grade, regardless of gauge, regardless of price and ornamentation. A field gun may be a field grade, but it may also be several steps above that in terms of fit, finish, engraving, etc--depending on what the owner chooses to carry afield. And it may be a 9MM if he's out shooting sparrows.