RSMo 21.730.3(2) In any jurisdiction in which the open carrying of firearms is prohibited by ordinance, the open carrying of firearms shall not be prohibited in accordance with the following:
(a) Any person with a valid concealed carry endorsement or permit who is open carrying a firearm shall be required to have a valid concealed carry endorsement or permit from this state, or a permit from another state that is recognized by this state, in his or her possession at all times;
(b) Any person open carrying a firearm in such jurisdiction shall display his or her concealed carry endorsement or permit upon demand of a law enforcement officer;
(c) In the absence of any reasonable and articulable suspicion of criminal activity, no person carrying a concealed or unconcealed firearm shall be disarmed or physically restrained by a law enforcement officer unless under arrest; and
(d) Any person who violates this subdivision shall be subject to the penalty provided in section 571.121
Firearms legislation preemption by general assembly, exceptions — limitation on civil recovery against firearms or ammunitions manufacturers, when, exception.