Its main parts were a removable barrel with an integrated flash suppressor and gas cylinder, a receiver with the rear sight, a perforated barrel shroud/guide with the front sight, the bolt and locking flaps, the bolt carrier and gas piston rod, a recoil spring, stock and trigger mechanism group, a bipod for firing from prone positions, and the previously-mentioned pan magazine. In total, the first versions contained only 80 parts, indicating both the simplicity and ease of manufacture of the design. Early versions had 26 transverse cooling fins machined into the barrel, but it was found that these had little cooling effect and so were deleted in 1938, further easing manufacture.