Masterpiece Arms are now selling their MPA (Mac-10 clone) carbines and pistols chambered in the .460 Rowland cartridge.
The .460 Rowland was originally developed a decade ago as a magnum power cartridge suitable for the 1911 pistol. It is about 10% more powerful than the 10mm Auto. I have not seen evidence of the .44 Magnum performance claimed.
This video entertaining video demonstrates the .460 MPA guns. It is worth watching, if only to see the concrete block wall dismantled
Prices start at $579 for the pistol and $853 for the carbine.
[Hat Tip: Tactical Life]