The K919 is Atlas Defense's premier submachine gun configuration of their modular weapons system. This modularity allows for any weapon within the Model K series to be configured into another role if necessary. For example, you can convert the K919 into a K556/K223 for any long-range battles (and K556/K223's can be converted into any other caliber designed for AR-15's). Of course, the basic K919 has a relatively low recoil, giving this weapon greater accuracy than some other submachine guns. The military forces that use this weapon system praise it for its modularity.
K919 (c) LuvFyaro