HERE ARE PICS OF THE 2 A.H.FOX 12 GA. PATTERNS. THE ONE ON THE BOTTOM IS A SQUARE FRAME. LOOK AT WHERE THE WOOD MEETS THE FRAME IN THE JOINT BETWEEN THE TOP TANG AND RCVR.(MARKED IN DARK PEN) IT IS ALMOST SQUARE. THE ONE ON THE BOTTOM IS THE ROUNDED FRAME. THE WOOD IN THE SAME JOINT IS ROUNDED LIKE UNTO A PENCIL ERASER. (MARKED IN WHITE MARKER) MOST 20 AND 16 GA A.H.FOXES ARE LIKE THE BOTTOM EXAMPLE. ALMOST SQUARE. P.S. THIS GOES FOR A.H. FOX GUNS ONLY, THE FOX MODEL B AS MADE BY STEVENS/SAVAGE IS TOTALLY DIFFERENT.