RSMo 571.030. 1. - Unlawful use of weapons--exceptions--penalties - A person commits the crime of unlawful use of weapons if he or she knowingly:
(8) Carries a firearm or any other weapon readily capable of lethal use into any church or place where people have assembled for worship, or into any election precinct on any election day, or into any building owned or occupied by any agency of the federal government, state government, or political subdivision thereof; or
8. Unlawful use of weapons is a class D felony unless committed pursuant to subdivision (6), (7), or (8) of subsection 1 of this section, in which cases it is a class B misdemeanor, or subdivision (5) or (10) of subsection 1 of this section, in which case it is a class A misdemeanor if the firearm is unloaded and a class D felony if the firearm is loaded, or subdivision (9) of subsection 1 of this section, in which case it is a class B felony, except that if the violation of subdivision (9) of subsection 1 of this section results in injury or death to another person, it is a class A felony.Risky behavior. Should not be illegal but it is, the OCer can be reported to LE and be arrested regardless of any agreement between he and the church.RSMo 571.107. 1. - Permit does not authorize concealed firearms, where--penalty for violation.
1. ... No concealed carry permit issued pursuant to sections 571.101 to 571.121, valid concealed carry endorsement issued prior to August 28, 2013, or a concealed carry endorsement or permit issued by another state or political subdivision of another state shall authorize any person to carry concealed firearms into:
(14) Any church or other place of religious worship without the consent of the minister or person or persons representing the religious organization that exercises control over the place of religious worship. Possession of a firearm in a vehicle on the premises shall not be a criminal offense so long as the firearm is not removed from the vehicle or brandished while the vehicle is on the premises;
2. Carrying of a concealed firearm in a location specified in subdivisions (1) to (17) of subsection 1 of this section by any individual who holds a concealed carry permit issued pursuant to sections 571.101 to 571.121, or a concealed carry endorsement issued prior to August 28, 2013, shall not be a criminal act but may subject the person to denial to the premises or removal from the premises. ...