A Modular weapon (or Modular Weapons System) is a weapon that allows for many modifications. Modularity has become a major attribute looked for by today's military and law enforcement because they can bulk buy one or two models of rifle, then bulk buy hundreds of add-on modules (grenade launchers, laser pointers, scopes or torches) which can be used with every other rifle.One of these rifles is the XM8, which was being considered as a M16 and a M4 replacement in the US military.