The VIS utilizes conventional “off the shelf” barrels with the use of a special barrel nut (provided with the VIS upper receiver kit). 

Four M1913 Picatinny rails come equipped with each system (3, 9 and 6 o’clock position), with one of the rails being continuous at the 12 o’clock position.

The lower handguard is removable to give access for an installation of an M203 Grenade Launcher. All kits come standard with a light weight removable lower handguard. A strengthened lower handguard which accepts a rail mounted M203 or other rail mounted weapons will be available as an option.