Zee, there is a very shallow gap between the 2 crimp grooves in that 388 gr cast HP that I make. For that reason I seat in the bottom crimp groove. Glenn crimps in the top crimp groove but you can shear off that small amount of lead between the 2 crimp grooves, many have had that happen. Plus it changes pressures.
Glenn has also shot that bullet completely through a large bull bison with an exit.
Dick