I have had some of my .357 cases bulge with a seated bullet either lead or Jacketed in some of my loads.
It looks ugly..... but they shoot great.

It is just the way the case is and the diameter of the bullet.
If it fits ok in the cylinder, there should be no real problems.
I had some old Speer 158gr SJSP that really looked ugly when loaded.



Jepp2;
You still have some W540 !! Sweet.