http://www.weaponsguild.com/forum/index.php?topic=43374.0

another breech lock method for a pistol

TRX
September 08, 2013
US Patent US8065950, "Automatic Pistol" by Hans Wrage & Co. Gmbh, 2011. It uses a fixed barrel and a slide like some of the SIGs, with an outer slide and an inner breech block. Except with this design, the breech block is locked to the barrel and lugs on the slide unlock it from the barrel. The slide gets its impulse from an annular gas piston on the front, like a Wildey. So it's a locked breech, gas operated pistol in a 1911-ish form factor.

It would still be fairly complex to build, but it's way simpler than a Wildey or Desert Eagle.

http://www.google.com/patents/US8065950