The BWN RK-5 was a resounding success throughout the twilight years of the 20th century but as the 1990s drew to a close the RK-5 was out of date. Enter the NEXUS program and it's end result the RK-15. The RK-15 stemmed from the need to have a 5.56 replacement for the RK-5 the was not the 7.62 of the RK-12. The RK-15 first saw use in the marines during operation Dragon Claw (2008). As the RK-5s obsolescence became evident the need for a better gun became more pressing. However the RK-15 only saw widespread adoption in 2023 when it was issued to all forces of the federation. It was intended to be much more customizable then the RK-5 and originally came with the option of 4 various configurations and had the option to add 4 more. It would become the standard issue rifle by the beginning of the 2nd cold war between the Federation and the Union.