When it comes to antis I don't worry about what particular phrase I use for any firearm, because as many in this thread have already pointed out, no matter what word you use they will always continue with their irrational beliefs and rantings. However, with lay people (I am not talking about antis, but those who are at least neutral with regards to guns) I have stopped using terms like 'semi-automatic' or 'auto-loading', and only use the term machine gun for machine gun (I don't use 'automatic'), because so many of them (and even some gun owners) are sometimes confused as to what the terms mean.
Too many times I have been in or overheard firearms discussions among people where the term 'semi-automatic', 'auto-loading', or 'automatic' was used to describe a self-loading rifle, shotgun, or pistol, and one of the people believed it meant the firearm was a machine gun of some kind. When discussing firearms with acquaintances whose firearms knowledge limits I don't know, I only use terms like handgun, rifle, or shotgun, and then only get into the action type (i.e. bolt action, lever action, pump action, revolver, self loading, etc.) or other characteristics, if they start wanting to know more specifics, and then I make sure I am clear what the terms mean. Of course its different with people who I know have firearms knowledge (like those on this board), and with those people I know I can use all the usual terms without there being any confusion.