The Lightrifle is a forerunner weapon encountered in the Halo 4 teaser trailer, it seems to be the forerunner counterpart to the UNSC DMR and the Covenant Carbine
Sources
E3 2012 Halo 4 gameplay trailer,3:41
The Lightrifle is a forerunner weapon encountered in the Halo 4 teaser trailer, it seems to be the forerunner counterpart to the UNSC DMR and the Covenant Carbine
E3 2012 Halo 4 gameplay trailer,3:41