Since you can run 40, and even 10mm from a blowback (if you really want to) I'm sure SIG can be done without incident. I suspect you'd need a pretty massive bolt to make sure things are safe, and that would then mean you'd have some nasty slap when it bottoms out in the receiver. Blowbacks just have trouble going much above 9mm without getting heavy or unpleasant to shoot (45acp is about as high as you can go, because of its low pressures that allow a lighter bolt to be used without case failure)
"I don't believe that the men of the distant past were any wiser than we are today. But it does seem that their science and technology were able to accomplish much grander things."
-- Alex Rosewater