The attempted robbery happened about 6:20 p.m. Sunday, The Kansas City (Mo.) Star reported.
One of the three robbers pulled a gun and waved it in the manager's face, demanding cash, police said.
As the manager was seemingly complying with the request, the suspect reached over the counter waving the handgun. The manager then grabbed the revolver, police said.
The three suspects backed away from the counter and tried to flee, first running into a locked door before escaping through an unlocked one.
Police described the suspects as three black males ages 18 to 27, and all about 5-foot-10.