The Aptus evolved from DRD's popular Paratus rifle, utilizing the same patented internal recoil and quick barrel change technologies in a smaller, even more discreet unit. The internal recoil system eliminates the standard buffer tubes and springs associated with most AR style rifles. This special feature allows it to be fired with the stock folded and maintain in the ready for close quarter battle situations. The embodiment of discreet and designed for compact portability, the Aptus can go from box-to-built in 60 seconds or less without the use of tools. DRD has eliminated the need for an additional upper to change calibers, giving you the ability to change between 5.56mm or .300 Blackout with the swap of a barrel. Includes Ambi. controls, left side charging handle, 2 mags and hard case. Does not include extra barrel.