Mitch,
Someone mentioned Carr's in Taunton (look for the thread titled "Carl?"). Yes it is mis-spelled.
Maybe BassPro in Foxboro? Check with them first before driving there to make sure that they have what you need. IIRC, we were told that they had powder and primers and that you might have to ask for them as they may not be on the floor. Ask about bullets, perhaps they can special order them for you?
As for gun shows, the next worthwhile one for reloading supplies is in Marlboro on Jan 26 & 27. [NOTE: Springfield (Big E) does NOT allow any ammo in their buildings, thus only 1-2 dealers sell in a tent located outside the building. Therefore no real selection and higher prices due to no competition and not worth the trek to buy components.]