The Flak 43 was a Rheinmetall design and featured a completely new gas operated breech mechanism and numerous speed changes to manufacture. It did continue to use existing ammunition and the barrel remained basically the same as the Flak 18, 36 and 37. Changes in speed manufacture meant that only 1000 man hours were needed to manufacture instead of the previous 4320 man hours. Rate of fire, traverse, and elevation speeds was increased making the Flak 43 a great improvement over the existing guns.