Developed by the weapons research division of the UNSC this early prototype was said to be heavily favored and influenced by feedback generated from the Spartan program. Spartans requested that their Assault Rifles have greater accuracy for mid to long range battles engagements so testing began. Data acquired from these tests eventually yielded such weapons as the DMR and ultimately the Battle Rifle which helped humanity prevail against the Covenant.
This is the only prototype known in existence to have made it off the planet Reach before the Covenant invasion.