The SMG Guns MK42 – as they’re calling it – is a modernized and reduced-cost FG-42 for practical competition shooters and civilian users. Gone are superfluous, cost-adding details necessary to a perfect reproduction, like the proprietary scope rail, “pull-out” selector, sheet metal magazine port doors, and original FG-42-style sheet metal bipod. Instead, the MK42 has a 1913 scope rail, 1913 bipod mount, AR-15-compatible pistol grip mount, and a shorter and lighter barrel. The initial prototype seen in the video retains the wood furniture of the reproductions, as well as the original design of muzzle brake. These will probably be changed in future versions.
The FG-42 was one German weapon virtually all of their enemies took note of during and after the war. In particular, the United States felt the weapon was a superb combination of firepower, accuracy, and light weight. The M60 machine gun was derived directly from both it and the MG-42.
For the full (and trully fascinating) FG-42 story, I highly recommend Death From Above: The German FG42 Paratroop Rifle available through Amazon. More information about the SMG Guns reproductions of the Type 2 version of the FG-42 can be found on their website, and also via the Forgotten Weapons YouTube channel.