Though it seems the thread has moved in the direction of 30-30 AI I'd like to chime in, in a slightly different direction. A friend came into a Wesson two-trigger rifle chambered in 30-30 Wesson but whose bore was absolutely worthless. He's a pretty good non-professional gunsmith. He relined the bore with a 25 cal liner and chambered it in 25-20.
It's a party to shoot with cast bullets - accurate as all get-out. And it put an old gun back to work.

fiery, dependable, occasionally transcendent