Inspired by the selective-fire HK416 rifle in use by special operations forces around the world, the MR556A1 is Heckler & Koch's nod to civilian enthusiasts. With the company's proprietary gas-piston operating system, it promises to be extremely reliable. The MR556A1 has a 16.5-inch barrel and weighs 9.04 pounds. MSRP is $2,995.