You might need "small base" dies for the 7400 or loaded rounds will not chamber. Semi autos and pump guns usually need the lower part of the shell sized a little more.
Long ago I loaded the .270 for a Rem 760 and never had a problem using regular dies but I have seen many others where a round would not chamber. Easy to see by sizing a fired case and dropping it in the chamber to see if the action closes and locks easy.