I have seating stems for wadcutter, semi-wadcutter, round-nose, and a few others in several different calibers that I load regularly. After tens of thousands of rounds of ammunition produced about the only thing I have yet to see is a seating stem that is perfect for any application.

Round-nose seating stem may apply some compression to an exposed lead hollow-point bullet tip. Semi-wadcutter stem may impress a slight, but noticeable, ring on otherwise perfect bullets. Wadcutter stem will always result in a flattened spot on the nose of any bullet seated.

Same issues with the Lyman and RCBS lubricator-sizer machines. Hundreds of "top punch" profiles, some of which may be perfect for one cast bullet, but most of which are "close enough".

With a well-equipped machine shop and a skilled lathe operator we could probably turn out a perfect seating stem for any given bullet. Not having access to such luxuries I have always settled for close enough!