Not counting "Jug" chokes there were mainly two types of choke used. "Conventional" choke had a cone followed by a parallel section. "Taper" choke was strictly a cone with no following parallel. Full choke on some Lefevers which used the taper choke were as long as 4". This was longer than the entire length of many conventional chokes. With either type more open chokes were normally shorter than was Full choke.
I have NEVER sen the term "Extra Full " used in any old literature to describe the choke in any of these older guns. Poly-Choke made models which were marked for both Reverse & Extra Full though both were likely Wishful Thinking.
I do not at present have a Fox to check but to the best of my recollection they also used the Taper Choke.
Also I have never seen any gun on which the choke was a taper for the full length of the barrel as one so often hears spouted on some gun which will "Kill Farther & Deader" than any other gun ever made.
