The KS family of rifles was unveiled at military small arms conventions in 2022 as being developed for an international special operations forces (SOF) requirement.

[2] In September 2023, the British Armed Forces selected the KS-1 rifle under Project Hunter to replace the L85A2-A3 and L119A1-A2 rifles used by the British Army Special Operations Brigade and elements of the Royal Marines including strike companies and the Surveillance and Reconnaissance Squadron.

[4][5] Knights Armament's submission (KS-1) was selected over other notable competitors including Heckler & Koch, SIG Sauer, Daniel Defense, and Glock.

[3] The UK Ministry of Defence (MoD) contract includes a £90 million option to purchase up to 10,000 rifles over the next decade.

This makes the KS rifle one of only three fully-ambidextrous M16/M4-style platforms fielded by militaries along with the Modular Ambidextrous Rifle System (MARS) from Lewis Machine and Tool Company and the M6IC from LWRC International, as well as one of six in total including the Radian Ambidextrous Dual Action Catch (ADAC), American Defense ADM, and the Primary Weapon Systems Mk 1 MOD 2 lower receivers that were developed and released after 2023.

The KS rifles feature Knights Armament's Quick Detach Coupling (QDC) flash hiders and a drop-in two-stage match trigger.