Magpul PDR

The Magpul PDR (Personal Defense Rifle) is a prototype bullpup-style 5.56×45mm NATO carbine unveiled by Magpul Industries in 2006. Although halted in development as of 2011 it has garnered some attention, largely due to its "futuristic" appearance. The system consists of a gas-operated bullpup carbine intended to replace some submachine guns, M9 pistols and M4 carbines while still offering the rapid fire and range of a M4 carbine in an ultra compact firearm.
The PDR is one of the few personal defense weapons designed to use a standard caliber to simplify the logistics. The method of operation is a short stroke gas piston. It is striker-fired, features an ambidextrous ejection system, and ambidextrous controls.
The PDR-C (Compact) features an FN P90-style pistol grip and ergonomics offering a more compact weapon, while the PDR-D (Direct) uses a more conventional pistol grip with vertical grip (similar to a Steyr TMP) and safety nub to keep users from injuring themselves.