Mo. Rev. Stat. § 571.050
571.050 Possession of defaced firearm, penalty.
571.050. Possession of defaced firearm, penalty. — 1. A person commits the crime of possession of a defaced firearm if he knowingly possesses a firearm which is defaced.
2. Possession of a defaced firearm is a class B misdemeanor.
(L. 1981 H.B. 296)