At ranges between 400 and 800 m (437 and 875 yd), the then available small arms capable of returning effective fire, were the general-purpose machine gun and the bolt-action sniper rifle.

These weapons chambered for the fully-powered 7.62 mm NATO cartridge were not well suited to increase the effective engagement range of the British eight-man rifle sections.

The LM308MWS was submitted for the British Ministry of Defence's Urgent Operational Requirement (UOR) for immediate deployment of a semi-automatic 7.62 NATO caliber sharpshooter rifle in Afghanistan.

[12] Updated MARS-H based L129A2 designated marksman rifle chambered in 6.5 mm Creedmoor with an 18 in (457 mm) barrel, a fully adjustable DMR stock and lengthened hand guard, a Leupold Mark 5HD 3.6-18×44 M5C3 Desert IR telescopic sight with TREMOR3 reticle, a HuxWrx suppressor, an Envision Technology ballistic calculator, and a Pixels-on-Target thermal sight was adopted in 2023.

[17] The upper receiver still uses a gas-operated, rotating bolt (internal piston) system like the L129A1, but the hand guard attachment points on its sides were changed to be M-LOK compatible.