Bigham
Favorite Answer
Neck turning is essentially a finishing operation, evening out neck thickness to a specific size. It would be quite counter-productive to do it before you've even sized the brass into the correct shape.
Similar concept with trimming, just with the length instead of neck thickness.
As far as the order of turning vs trimming...really wouldn't matter. But the important part is that BOTH of them need to happen AFTER sizing. There's not much point in doing either before you've even sized the brass.
So:
YES: size -> trim -> turn
YES: size -> turn -> trim
NO: any other combination of the 3
John de Witt
The former.