A quick teaser video of one of the Classic Army Advanced Series AEGs, the CA083M 13" KeyMod AEG... "The Classic Army M4 ARS4-10 is an M4 with a 13in. free float keymod rail and an 14.5in. outer barrel. The monolithic profile rail system has a standard picatinny configuration on the top rail, allowing for fitting of standard railed mounted scopes or other accessories. The gun features an ergonomic grip, flip up front and rear sights, and a retractable crane stock, and a sling adaptor plate.