From their Website:
The K100 uses a rare locking system, shared by the Beretta Cougar, PX4 Storm, and Brügger & Thomet MP9 which employs a rotating barrel lock, which in the K100's case is cammed by a cross pin. When the pistol is fired the barrel and slide move backward together for about 3/8ths of an inch while the barrel is cammed counterclockwise by a flat, twisting, helical "cut" in the barrel extension. Once the barrel and slide have moved back to the point where the barrel has twisted about 45 degrees to the left, the slide is free to continue traveling back while the barrel's travel is arrested by its interface to the frame via the barrel extension. On the K100 the Beretta's barrel extension cam cut and cam tooth are replaced by a frame-embedded crosspin and a barrel extension "cut" with rounded surfaces which engage it. As such, there is no transfer block per sec, and the barrel and barrel extension directly interface with the frame via the crosspin.
I'm wondering just how well that crosspin will hold up to tens of thousands of rounds?