To remove Dowel, get a #10 3" Deck Screw or any other large Wood Screw and first take a 1/8th drill bit drill down the middle of Dowel, now run Screw into Dowel at deep as you drilled to get a real good bite. Pull with all your might. The Barrels Grooves has gotten hold of the Dowel, which means the Dowel won't come out straight, but will now want to twist with the grooves of the Barrel. You may need to spray some WD40 or some other Spray Oil into Barrel to help grease things up to make slippery to help extract.
As to the Shell Casing, if you haven't ripped off the Primered End, you can extract the Primer and run a Screw into it and Spray some Acetone on Casing and Breech to break up the Shellac and extract. All this will take some time, but wil save a good chunk of change over taking to Gun Smith and having them laugh at ya after you leave.
If you think you can't do this, send me the Barrel, I'll pay the Postage. Just don't mar and tear it up then say, "this isn't gonna work, we're gettin a new Barrel."