The original conical for the Navy Colt weighed 140 grains in pure lead. The loading aperture in the barrel boss is designed for bullets in this weight range. Heavier (longer) bullets don't work with the factory loading system.
None of these conicals is a true round nose. In fact, the loading aperture on a Navy Colt is in the shape of these projectiles. Real round nose bullets and anything with a meplat isn't going to work. With the .36 conical, the idea is supposed to have been to give the Navy a throw weight equal to the .44 Colt's ball.
Then the overseas factories started building .44 caliber "Navies"--a gun that never existed. But they didn't alter the loading aperture, so trying to load a .44 conical is not happening. The original .44 Colt conicals varied some, but 219 grains seems to have been the heaviest.
If you don't mind grinding away on your revolver, you may be able to open up the aperture enough to take the larger conical. But space is pretty tight in that area, so I would measure very carefully. On my Navys, all of .36 caliber, I don't think there is any way I could ever get anything longer than the 140 grain standard conical in there. Good luck.