I don't know what company's dies you are using but, most manufactures will recut your seater stem to a certain bullet for a small fee if you send them your seater stem and a few bullets.
The seater stem is not cut for the design bullet you are using.
You also can use some two part epoxy to correct your problem. Just clean you seater stem well and put a small amount of epoxy inside of the stem where the bullet is seated and reinstall it in the die and then put the die in your press and close it lightly on one of your loaded rounds that has the new bullet.
Let the epoxy set the required time and it should work fine and not ring the bullets anymore.