Randy says that until you cut off the choke, you don't know if the bore is too far off center for the screw in choke system.
Here are my notes:
1) I am set up for 12 ga Rem Choke in a few pilot sizes.
I can only modify half of my massive beater shotgun collection.
Many of the barrels are too thin for my 32 threads per inch system.
I need a barrel to be .845" diameter.
2) Winchoke is also 32 TPI and needs .845"
3) The Tru Choke system with 44 TPI needs at least a .825" barrel muzzle.
4) The Tru Choke Thinwall aslo with 44TPI needs at least .805"