Just working on the outside of that crown will make it a lot better. The only book I read on gunsmithing told how to cut and crown a barrel without a lathe. Forty years ago so I forgot some of the details. Cant even remember the name or author.
On the inside portion of the crown he would chamfer the bore with a 45 degree bit then use some brass ball shaped laps in a brace (Before power drills were common) to work it out. On the OD I think the procedure was to file then sand it to shape.

A couple of quick questions, when the CMP was handing out all those Krags in the thirties, they did not come with the bayonets did they? How did a person get them?