In 2009, Lewis Machine & Tool Co was contracted to supply the
British Ministry of Defence (MOD) with 440 LM308MWS 7.62×51mm rifles under the official service designation as the
L129A1. Its
NATO Stock Number (NSN) is 1005-99-226-6708. As of December 2014, over 3,000 units have been supplied to UK forces. During the
war in Afghanistan British light infantry units sometimes found themselves outranged by small arms beyond the effective range of their assault rifles and light machine guns chambered for the intermediate 5.56 mm NATO cartridge. At ranges between , 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. Other rifles submitted included the
FN Herstal SCAR-H,
Heckler & Koch HK417 and
Sabre Defence XR-10. LMT's rifle was chosen, earning it the L129A1 designation, and entering service in April 2010 in Afghanistan. One member (termed the "sharpshooter") of the British rifle sections, was issued an L129A1 instead of an assault rifle. The standard optic for the L129A1 is the TA648-308 6×48
Trijicon ACOG providing a 8 mm
exit pupil for ample light gathering and a wide field of view. Two locking bolts accessible from the right side of the receiver with a basic tool lock a barrel extension and make the barrel unit user removable within minutes with a return to zero of the same barrel. It features an
twist rate to fire standard 144-grain 7.62 mm ball up to 168-grain BTHP ammunition used by NATO, but the official issue rounds are 155-grain L42A1-A3 sniper and L59A1 "High Performance" ball ammunition. The ACOG is mounted to a Picatinny rail to which is fitted a Trijicon RM01 1 x Ruggedized Miniature Reflex (RMR) for Close Quarters Battle use. A
Sniper Support Weapon (
SSW) version, also designated L129A1, was adopted for use by the second man in each sniper team and is fitted with a
Schmidt & Bender 3-12×50
telescopic sight and a Surefire suppressor. Within the
Royal Marines at least, an improved Modular Ambidextrous Rifle System (MARS-H) based
L129A2 version chambered in
6.5 mm Creedmoor with an barrel, a new Leupold scope, a HuxWrx
suppressor, an Envision Technology
ballistic calculator, and a Pixels-on-Target
thermal sight was adopted in 2023. == Variants ==