.40 HP's
I'm not completely sure of this, but I think BHP"s from advent of those chambered in .40 forward, had slightly beefier frames to accommodate the pressures generated by the .40 S&W v. the milder 9mm
Seems like I have read BHP fans bemoaning the change as it spoiled the feel of the classic BHP. I don't know if an additional 5000 units of pressure generaated by the .357SIG (if indeed those numbers are right , would threaten the "new" BHP frame or not.
It is pretty common to see various pistols with barrel swaps between that family of cartridges.........I dunno