I just found this online so I am not sure how reliable and if I understand it correctly but here it is.
1. The general assembly hereby occupies and preempts the entire field of legislation touching in any way firearms, components, ammunition and supplies to the complete exclusion of any order, ordinance or regulation by any political subdivision of this state. Any existing or future orders, ordinances or regulations in this field are hereby and shall be null and void except as provided in subsection 3 of this section.
2. No county, city, town, village, municipality, or other political subdivision of this state shall adopt any order, ordinance, or regulation concerning in any way the sale, purchase, purchase delay, transfer, ownership, use, keeping, possession, bearing, transportation, licensing, permit, registration, taxation other than sales and compensating use taxes or other controls on firearms, components, ammunition, and supplies except as provided in subsection 3 of this section.
[Subsection 3 does permit regulation of open carrying of firearms, if such law is exactly like the state law.]
Does the bold section not say that local ordinances can only be exactly like the state law which in Missouri OC is perfectly legal according to state law?