Greetings,
I got a 500 S&W from Virgin Valley.  It's a SS finish, 22 inch length barrel.  I've only shot it at 50 yards so far during scope sighting in / initial load development, but those round will overlap at that distance.   The recoil of this thing is pretty severe IMHO.
From my experience so far I'd highly recommend the VV / 500 S&W combo.  I don't have first hand knowledge of the 50 Ak round.  However, be forewarned that VV uses another supplier for it's 50 caliber barrel blanks.  I believe the supplier name is something like "Mountain Man". 
B. Noz.