Yes a neck expander , if not required ... sure makes life a lot easier .
I find the best option to be a Lee Universal Neck Expander ... in truth it is a neck flaring tool but sometimes a flare is all you need ... like when seating gas checked boolits ... And Noe now makes true M-die style plugs you can order and use in the Lee Universal Die body ... order these much cheaper than a Lyman M-Die and in many more sizes than Lyman makes.
I don't do powder through expander dies ... so this is how you do it on a single stage press .
Gary