Try this trick for taking A TINY BIT off of the forcing cone.
Take the wedge out and turn the barrel on the arbor. You will likely need to hold the frame in a vise.
Sorry for using a junk pistol for these photos. But you get the idea.
Then put a thin file between the cylinder and the forcing cone. Put some sandpaper over the file. The purpose of the file is to give you a hard flat surface. (A file also does a good job of holding the sandpaper in one place.)
Then slowly work the barrel back and forth pressing down ever so lightly so as to remove metal from the forcing cone. Take the barrel off frequently and inspect the cone to make sure the process is doing what you want it to do.