The fire broke out around 2:25 p.m. at Clayton's Indoor Shooting Range on the 600 block of Easton Road in Horsham.
Chopper 6 was overhead as crews worked to contain the flames.
Firefighters battle blaze at indoor shooting range
Officials told Action News that crews were initially dispatched for a fire in the HVAC unit, but a cause has not yet been determined.
No injuries were reported.