use of sizing die after patching

[flintlokusa]

This all new to me . I was wondering about pp to 45 bore. A .444 bullet with BA paper , would measure out at .451 or so. I see people running the patched bullet thru a sizer ?? Would this work with a 450 sizing die ?? or should I start with some thing else ?? Appreciate all the help I can get . Will be using a Browning 1885 BPCR 45-70