Thanks for all the diagrams, they will surely come in handy. Thought I would document this one from start to finish, so here goes.
First pass, truing the end
Starting to take down the breach area.
Oh yeah, my friend's 1934 Lima lathe.
Starting to drill.
Surface prep for steady rest and boring.
And starting to bore. As of end of the day, bore is at 1.6 inches, a bit more to go for golf ball dimension of 1.728-1.730. Powder chamber is 1"x1 1/4".