One scoring method published in the American Journal of Political Science found Paul the most conservative of all 3,320 members of Congress from 1937 to 2002.
I'm sure you could find many instances when Ron Paul did not vote according to the conservative rule book. It depends how you define conservative. Paul's conservatism is basically constitutionalism. If the constitution does not allow it, he will not vote for it.
If some so-called conservatives think they can do it better than the Founding Fathers, so be it.