KS-1 rifle
Assault rifle
From Wikipedia, the free encyclopedia
The KS series of rifles are produced by Knight's Armament Company (KAC). They are designed as updated versions of their AR-based SR-16 rifles. The 13.7" KS-1 variant was adopted as the L403A1-AIW by the British Armed Forces in 2023 to supplement the L85A2-A3 and L119A1-A2 rifles used by Royal Marines and the British Army Ranger Regiment.
| KS Carbine | |
|---|---|
British Ranger Regiment soldier with KS-1 (L403A1) | |
| Type | Assault rifle |
| Place of origin | United States |
| Service history | |
| In service | 2023–present |
| Used by | British Armed Forces Republic of Korea Armed Forces |
| Production history | |
| Designed | 2022 |
| Manufacturer | Knight's Armament Company |
| Produced | 2022–present |
| Specifications | |
| Mass | 3.12 kg (6.9 lb) |
| Length | 818–869 mm (32.2–34.2 in) |
| Barrel length | 292.1 mm (11.5 in), 347.98 mm (13.7 in), 368.3 mm (14.5 in), 406.4 mm (16.0 in) |
| Cartridge | 5.56×45mm NATO |
| Action | Gas-operated, closed rotating bolt, Stoner bolt and carrier piston |
| Feed system | STANAG magazine |
| Sights | Folding Back-Up Iron Sights |
History
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.[1] 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.[2][3][4]
The KS-1 has been given the designation L403A1 and is known as the Alternative Individual Weapon (AIW) system.[4] The Royal Marines have purchased more than a thousand KS-1 rifles and the British Army has purchased 1,620 KS-1 rifles worth £15 million.[3][4] Knights Armament's submission (KS-1) was selected over other notable competitors including Heckler & Koch, SIG Sauer, Daniel Defense, and Glock.[2][5] The UK Ministry of Defence (MoD) contract includes a £90 million option to purchase up to 10,000 rifles over the next decade.[4] KAC is working with Edgar Brothers to distribute the weapon in the UK.[6]
On February 2025, the Royal Marines reportedly tested the KS-1 in Norway for use in cold weather operations.[7]
Design
The KS series features a self-indexing, highly-efficient gas system with a straight gas tube design. The fit of the gas system minimizes gas pressure loss between the gas block and carrier key. The gas block notably is held in place with a nut which simplifies removal and maintenance.
The KS rifles feature an enhanced bolt carrier group with Knights Armament's E3.2 Enhanced Bolt. It is a proprietary bolt which features an enlarged bolt face, dual ejectors, rounded bolt lugs, reduced diameter cam pin, and proprietary extractor and firing pin designs.[8] These features increase the firearm's durability and reliability.
Unlike most AR-style rifles, the lower receiver of the KS is fully-ambidextrous. The fire control safety, magazine release, and bolt catch/release are mirrored on both sides of rifle.
The KS rifles feature Knights Armament's Quick Detach Coupling (QDC) flash hiders and a drop-in two-stage match trigger. All current KS rifles feature cold hammer forged barrels which are chrome-lined. In addition, it utilizes Knight's Armament's proprietary free-floating handguard, the URX 6, which covers the entire length of the barrel and helps to protect the barrel from damage.[9] The current series of KS rifles is chambered in 5.56×45mm NATO and comes in four barrel length configurations (11.5", 13.7", 14.5", 16").
Variants
KS-1
13.7" heavy-profile barrel with mid-length gas system. The barrel features distinctive ball-mill dimpling for weight-relief and reduction of heat-induced barrel shift. When paired with a small high-efficiency suppressor, the KS-1 notably has a similar overall length to a 10.3" M4 carbine with a full-sized suppressor, but with higher muzzle velocity.[10]
L403A1
British military designation for the KS-1 model. Equipped with L900A1 Optics Suite (Vortex 1–10x low power variable optic in a Reptilia AUS mount, combined with an Aimpoint ACRO P-2 red dot sight in a Reptilia ROF 90 mount) and KAC QDC/MCQ-PRT Inconel 3D printed reduced backpressure suppressor.[11][12]
KS-2
14.5" barrel with mid-length gas system.
KS-3
11.5" barrel with carbine-length gas system. Its smaller size allows for easier stowing for transport, and less cumbersome to carry. With nearly 100% compatibility with other KS series rifles, it is the recommended choice for a secondary upper receiver for those with KS-1 or KS-2 rifles, or as a primary system for those that require a dependable, small, lighter carbine.
KS-4
16" barrel with "extended" mid-length gas system that utilizes a 15" variant of the URX handguard.
Users
South Korea: An unknown number of KS-3s are used by the Korea Coast Guard and the 707th Special Mission Group.[13][14]
United Kingdom: Designated the L403A1.[15] They are currently in use with the Royal Marines and the British Army Ranger Regiment as a replacement for the SA80.[15]
