An improved hand held spray gun. The spray gun includes at least one manual trigger which when squeezed moves a valve needle to initiate fluid flow. A knob is provided to adjust the maximum fluid flow when the trigger is squeezed. When the trigger is released, a compression spring returns the valve needle to its closed position. An over travel spring is compressed only if an excessive force is applied to the trigger to prevent damage to the spray gun. The over travel spring is stronger than the valve needle return spring so that it compresses only after the spray gun is fully on. If the maximum fluid flow adjustment knob is turned too far, compressed air is vented through the knob as a tactile warning to the spray gun operator to not turn the knob further. The vented air also may whistle to provide an audible warning that the knob should not be turned further.