Paul;
If your barrel is worn or oversize, the oversize can be determined by getting a soft lead sinker a little bigger than the bore and driving it through the barrel with a 1/4" wood dowel, then measuring bore and groove diameters.
Some times, a worn or oversize barrel can be made to shoot accurately with a .001 or .002 oversize hard cast gas check bullet, some thing about 18-24 Brinnell Hardness with a good lube.
Velocities of 1800-2500 fps are practical and the bullets have good penetration and expansion at ranges of 200-250 yds.
Molds for cast bullets with bc.'s .260 to .350 are available at very reasonable prices and the alloy needed is just wheel weights with a small[1-1.5%] Tin added and water dropped at casting.
Just some suggestions.
Happy shooting, Don