Monticello firefighters and MPD responded.
The fire is believed to have started in the back of the building.
The highway was blocked from approximately 6:45 until near 8:30, due to hoses and safety.
State police and ATF have been notified, as is the case with all firearms dealers situations like this
No injuries were reported, except for the rumor of a bystander several hundred foot away, passing out from the heat.