New 10" barrel, bullet stability problems

[amafrank]

First thing is to check the crown and make sure its clean, even and centered. Any deviation can cause problems.
Next try setting targets at 50 and 150yds and see what your groups look like. That will give you some idea whether or not the bullets are settling down or getting more wobbly.
Lastly try some different bullets. Some barrels and bullets don't mix well. Change your load as well. It seems that some powders will give you identical velocity but less stability.

Good luck
Frank