Yes, insofar as you are voting for someone who may vote that way in congress, but that does not mean you actually support that stance. No free thinking person agree's with every stance of either party and everything every member of that party does. But to say that there can't be a pro-gun democrat is just idiotic. There might not be many in a position of power, but there are many millions in the general population. You are allowed to have a stance that does not follow the party line, and it is not uncommon at all among normal people.