Most of my rifle brass for bottle-necked cases gets a light inside and outside chamfer. This process removes the “burr” left after case trimming. The inside one reduces the “shaving” of the bases of flat-based, jacketed bullets. The outside chamfet has no real function apart from clearing the aforementioned “deburring’. I am one of those folk who has taken to using the Lee “Factory Crimp” dies, gently, on bottle-necked cartridges.They certainly squeeze in the brass at th eend of the neck. Over-doing it will probably shorten the life of the cases, but “just enough” gives consistent ‘grip’ on the bullet, preventing “bullet float” in magazine-fed repeaters.

As usual, YMMV!