Nice little buck you got with that new rifle! Well done.
Instead of coning, might I suggest doing a re-crown to the one Rice machine cut. All you need is a piece of 320 grit emery or wet/dry and a cloth cleaning patch.
Run the patch down about 1", then using the end of your thumb pushing the paper or emery into the muzzle, rotate your thumb back and forth, every 5 seconds or so, rotate the barrel 180 degrees. After about 30 seconds, it will look much like this and make the ball and patch transition/forming into the bore much easier.
When finished, reach into the muzzle with needle nose pliers and pull out the patch with the 'grindings'.
Late season, fat animal and when it moves, the fat plugs the hole, for a time, usually. Especially with bears.