thumper
 n.— «That banger’s thumper is a double-deuce, and he packs a gauge. Translation: That gang member’s pistol is a .22, and he carries a shotgun.» —“Gang Slang Police Compile New Glossary Of Street Talk” by Peter Hernon St. Louis Post-Dispatch (Mo.) June 2, 1992. (source: Double-Tongued Dictionary)