M 16A4 is a full-size combat rifle with high accuracy in medium and long range shooting, which is mainly used by the US Marine Corps. But compared with the M4 carbine, it was too big and too heavy to be suitable for street fighting, and finally it was retired.
In 2009, the United States began to purchase HK4 16 series rifles and 4 19mm heavy barrels from Germany. The shooting accuracy is higher than that of M 16A 1, which leads to more shortcomings of M 16A4.
Intermediate M27 1AR(HK4 16)