“…where a state permits individuals to openly carry firearms, the exercise of this right, without more, cannot justify an investigatory detention.  Permitting such a justification would eviscerate Fourth Amendment protections for lawfully armed individuals in those states.” 

United States v. Nathaniel Black, 4th Circuit, U.S. Court of Appeals, No. 11-5804, February 26, 2013.

This means that in an open carry state a stop and frisk under Terry v. Ohio [sometimes called a “Terry stop,”] is not justified simply because someone is openly carrying a firearm.