The dies I used were Hornaday. They
have a sleve that falls below the die
that supports the case neck.I size,decap,
and clean the cases prior to using the
550 to prime,charge,seat. To crimp 375
I had to use another brand of die. I
could adjust the Hornaday to seat;but
not crimp. I like the Hornaday so I
am going to try the Lee "factory crimp"
die. Since you will be working with a
overall length 3/10 inch longer die
selection is critical. I think at one
time Dillon offered a 470 shellplate.