According to the wikipedia article on the Congressional Tea Caucus, that caucus has 60 members in the U.S. House of Representatives. Forty of them are from states that have either open primaries or top-two primaries. This observation is not meant to express any opinion about the Tea Party Caucus. Nor is it meant to express any opinion about different types of primary systems. Nor is it even meant to suggest any causation between type of primary system, and propensity of a state to elect Tea Party Caucus members.
Political scientists Boris Shor and Seth Masket have shown that there is no correlation between type of primary system, and degree of polarization and partisanship in state legislatures. Presumably that conclusion would apply equally to Congress, if they had studied Congress. But because the mainstream press regularly assumes that open primaries, or blanket primaries, or top-two primaries, produce more “moderate” politicians, this observation is being posted.
Michele Bachmann founded the U.S. House Tea Party Caucus, and she is from an open primary state.