As I have just finished restocking a Fox-Parker,(bottom gun) thought I would provide pictures for comparison. The Parker is a 2 Frame, by my direct measurements the Fox action tangs are a bit longer, about 1/2". The action length measured from breach face to end of the knuckle is essentially identical. Breach width is almost identical. The for-end tang on the Fox is longer by about 3/8" and as you can see the latch sits forward a bit. Picture for comparison.
