I have gotten my Segrist-rebored barrel (.338 X 10 twist in an original #3 octagon .32-40 bbl) for high-wall up and running now, but have a little problem.  I can drop a bullet into the chamber and push it home with a plunger and a lot of effort, but because of the size of the bullet and the thickness of the brass at the case mouth, I can't get a loaded round or even make a push seater or mechanical seater to hold the bullet while starting it.  How should I go about making the chamber neck larger without endangering the existing chamber and new bore?  Is there such a thing as a neck only reamer for this chamber, or should I plan to have to have one ground  ??? ?
Other than that one little hold-up, the rest of the project is going great!  With a plain Lyman tang sight and Beech front in globe position I just amaze myself!   
TIA for any suggestions and help any of you may be able to provide on this.
Regards, 
Charlie the Frog

Green One
When Pope made 33s he made both 33-47 and 33-40. I belive when the rifle was a muzzle Loader Pope left the chamber a 40 but when the rifle was a breach seater he re-boared to 47.
You might try using a plugged case with the plug that skicks out the same size as the bullet.

40 Rod