The airline transport pilot reported that during the landing roll, the airplane immediately veered right as the tailwheel contacted the runway. The pilot applied full left rudder to no avail, and the airplane ground looped to the right. The left main landing gear collapsed, and the left wing and horizontal stabilizer were substantially damaged. The pilot stated that the right brake may have dragged and that the tailwheel may have tilted over during the touchdown. Postaccident examination of the runway marks, brakes, and tailwheel revealed no preaccident mechanical malfunctions or failures that would have precluded normal operation. The wind was reported as 30° right of runway heading at 4 knots. According to first responders, three passengers were sitting in the airplane’s front two rows, and one passenger and multiple bags were in the rear baggage compartment, which was not equipped with a seat. This likely resulted in the airplane having an aft center of gravity and increased the airplane’s tendency to weathervane into the wind and the airplane’s directional instability.