Ben-T;
That is correct re the Lefever. Their catalogs stated that after much experimention they had perfected the "Taper Choke" which was a taper from breech to muzzle. A number of writers have apparently read this & stated Lefever chokes extended for the entire bbl length. I have never personally encountered one so choke nor have any knowlwdge of anyone else who has found one so made. Further I have no reason to believe a bbl so choked would perform much different than a Cyl bore.
There were makers other than Lefever who used the taper choke rather than the conical/parallel but at present I don't recall just who.
In the Lefever catalog they "Guaranteed" 85% patterns with their full chokes for any shot size. I truly suspect they were counting on not many folks doing actual pattern counting, as that's a rather bold guarantee especially in deference to the shells of the day with card & felt wadding & many being loaded with soft shot.
