Jewelry store owner fires at armed robber, MLive.com, Michigan, 04/23/14

David Medawar, owner of Paul Medawar Fine Jewelry in Plainfield Township, Mich., was at his store when he spotted a group of four men near the front door. Medawar ordered his employees to a back room, as the armed robbers entered the store. Medawar and his father then armed themselves with handguns and retreated to the back room with the employees.
From a surveillance system in the secure room, Medawar spotted one of the thieves approaching. Medawar warned the criminal, “We have a gun. We will shoot you. Leave.” Undeterred, the robber continued into the room, prompting Medawar and his father to open fire. After meeting the armed resistance all of the criminals fled.
Medawar purchased firearms for the store following a robbery in 2010. The owner told a local media outlet, “We had taken measures to ensure that would not happen again… We were prepared when they came in, But God also protected us. He was watching over us.” 

Tobacco store clerk fires on robber, CBS-DFW, Dallas, Texas, 06/13/13

A man entered a game room and tobacco store in East Fort Worth, Texas, pretended to play a game and then drew a gun on a clerk and demanded cash. The clerk complied with the demand, but a second clerk, who had overheard the robbery from another part of the store, retrieved a shotgun and fired at the criminal, striking him in the knee and head, and ending the robbery.
When police arrived, the armed robber was taken to a local hospital, with police planning to charge him with aggravated robbery once he has recovered. Local media has reported that the armed clerk will not face charges. 

Resident fires at trio of burglars, The Palm Beach Post, Palm Beach, Fla. 05/21/13

A group of three burglars approached a home in Delray Beach, Fla. and knocked at the front door. When they received no answer, the trio went around to the back door and attempted to break inside. A resident of the home noticed the would-be intruders, retrieved a gun and fired at the criminals, striking one and causing all to flee in a nearby getaway car.
Police captured all three burglars a short time later at the Delray Medical Center, where the injured burglar underwent surgery.