Borrow a caliper. Check the inside diameter of the chambers. Then get a ball that is a couple thousands bigger than the diameter of the chamber. If the chamber is .440, get a .445 to .45 ball. If it is .45, get a .454 ball.
The thing is that you want a ring of lead to shave off the ball as it is pressed into the chamber. This helps to keep the fire from one chamber explosion from going into another chamber and setting off a chain fire.
You also need to check out the stickies on loading cap and ball guns, and find some Bore Butter or felt wads to fit.
The Doc is out now.
