WESTMINSTER, Colo. - A man accused of reaching for a concealed gun outside of a Walmart store was tackled and pinned to the ground by customers and employees, according to Westminster police.

Police say the gunman, Cassidy Ray Rhoads, was in possession of a loaded Glock. He faces possible charges of improper possession of a weapon by a previous offender, felony menacing, unlawfully carrying a concealed weapon, reckless endangerment and disorderly conduct.

Police say Rhoads was shouting in the parking lot of the Walmart at 95th Avenue and Sheridan Boulevard Friday when a customer told him to stop being so vulgar. The two argued, and the customer tackled Rhoads after Rhoads allegedly reached for a gun. Customers and employees held Rhoads, pinning him to the ground until police arrived.

Police say Rhoads' criminal history prevents him from possessing a firearm. Officers are investigating how Rhoads got the gun.

Rhoads was taken to a hospital because he was unconscious after hitting his head on the ground during the struggle.

Investigators say drugs may have contributed to Rhoads' behavior.

7NEWS checked Colorado court records.  Rhoads has a lengthy police record including burglary and drug-related charges.