The above link will take care of everything lol. I put a slightly oversized hinge pin in my encore. Right now I have a short 30 30 barrel that will shoot a cast 150g WFN 1900 fps bullet consistently 1.75 inches at 100 yards. Very satisfactory for the bullet. Jacketed does markedly better.
Break action guns, especially nice ones, can be plenty accurate for anything typical/practical. I do know that the TC brand barrels can be hit and miss... I have sold all of mine due to accuracy issues with cast bullets and goofy throats on them. I have not had any problems with my MGM, and will likely buy another later.
The rimmed cartridges are generally your encore/contenders best friend too!