I am not sure of your measurements so I would like to play back what I think you are saying: I believe you are measuring differences between the bore and the constictions rather than actual diameters. Starting at the muzzle and working towards the breech you have a constriction of .035 over 3 inches. For the next 2 1/2 inches you have no further constriction which means your .035 is now 5 1/2 inches long. My interpretation of 'no futher constriction' means to me that it did not revert to the bore diameter, nominaly .729. For the next 2 1/4 inches you measure a further constrictin of .024 which means you wind up with 5 1/2 inches of ,035 and 2 1/4 inches of .059. I have never seen or heard of a choke like that on any gun. Not only the amount of constriction but also the long length. I have measured odd chokes such as on modern Ljutic SBT's which have an opening beyond the normal bore diameter a couple inches before the choke forcing cone. Also Becker of AH Fox fame was reported as providing his magical chokes gradually over the lenght of the barrel from breech forcing cone to muzzle.
The first thing I would do is pattern the gun. I have read that overly tight constrictions tends to spread the pattern. The second thing I would do is find/borrow a bore gauge and measure actual diameters. I don't know what else to say except good luck and tell me about the rest of the gun: grade, barrel lenght, type of escutcheon, etc