Larry,
I experienced the same problem with a Traditions 50 cal. m/l I received last year. Had a heck of a time getting sabotted bullets down the bore. I wrote Traditions and they suggested changing sabots. I happened to be in Wal-Mart one day when I found some of the non-sabotted 295gr. HP Copper-Clad PowerBelt Bullets (with the green skirts). They loaded very easily and Wahoo!!! they were very accurate too. I found using ff Triple 7- 90 grains that I was getting consistant results. Good Luck!
Oh, if you want to loosen up that barrel, I'd consider using some J-B bore compound paste along with Kroil, and use a nylon brush to get the sharp edges removed! Let us know how you make out. Incidently, check Brownells catalog to order the J-B Compound and Kroil.
Jim