Lewis Machine & Tool Company (LMT) is an American armaments company founded by Karl Lewis, in 1980. LMT manufactures weapon systems including a variant of the M4 carbine and the M203 grenade launcher. LMT products are used by the military forces of the United Kingdom, New Zealand, Estonia, and the United States. LMT formerly produced forged FAL receivers for Illinois-based DS Arms.

The M203 is a single-shot 40 mm under-barrel grenade launcher designed to attach to a rifle. It uses the same rounds as the older stand-alone M79 break-action grenade launcher, which utilizes the high-low propulsion system to keep recoil forces low. While compatible with many weapons, the M203 was originally designed and produced by the United States military for the M16 rifle and its carbine variant, the M4. The launcher can also be mounted onto a C7, a Canadian version of the M16 rifle; this requires the prior removal of the bottom handguard.