#556.5.56x45
L. James Sullivan's Rifle Patent – The MGX
In 2012, AR-15 designer Jim Sullivan applied for a patent for a new rifle design. Apparently based on his Ultimax 100 light machine gun, the rifle features a quick-change barrel, a guide-rail-less receiver with a “backbone” guide rod attached to the lower receiver, a modular trigger pack, and dual firing modes in the open and closed bolt positions.
