Not necessarily right but not pertinent to your rifle.
Tapering the bore by .001 or less increases accuracy, as discovered by the bench rest rifle makers over 100 years ago. It's hard to get that taper with conventional machinery so was pretty much ignored for mass production until hammer forging became popular. So today some quality hammer forged barrels have a bore taper.
But not your 91/30. And I doubt that you'll ever get one hole accuracy, so I'd have cut the barrel with a hacksaw, filed the end flat and square with the bore, then "crowned" it by chamfered it a little with a brass round head screw dipped in valve grinding compound chucked in an electric drill.
I swear by Jupiter Optimus Maximus .... in the army of the consul Lucius Quinctius Cincinnatus and for 10 miles around it I will not steal anything worth more than a sestertius in any one day.