Inferior Rifles compare the HK MR556 A1 and A4 to show what is new with the A4.

In the comparison presented by Feldmutze, several key differences between the HK MR223A3 and the MR556A1 are highlighted. These differences encompass various components such as the buffer tube, the upper and lower receiver, and the barrel extension pin. Furthermore, the analysis also points out how these models differ from the HK416A5. The barrel of each model is examined, revealing distinct characteristics that set them apart.