Dallas Fire Rescue responded to a fast moving fire at the DFW Gun Club and Training Center in the 1600 block of Mockingbird Lane of Dallas. The range is a few miles west of Dallas' Love Field Airport.
There were between 50-100 patrons in the building when the fire broke out but they all escaped safely.
Nearly 100 firefighters battled the flames. A firefighter was treated for smoke inhalation.
Investigators believe the fire started when a tracer round was fired at a backstop.
"It flares up a little bit, whenever you fire it inside," said Dallas Fire Rescue spokesman Jason Evans. "At a gun range, it can easily catch that backing on fire."
Evans said no laws were broken. The fire is being ruled accidental. The department will not be filing any charges against the person who started the fire.
This is the same gun range where the roof collapsed under nine inches of rain in March of 2006. No one was injured in that incident. But several people were inside when the roof began to give way.