Have you contacted Sig directly?
Originally Posted by Ridgerunner665
Seems like they might be able to answer your question on a replacement bolt or carrier as well as if the new ones are drop in replaceable for the old ones (which I couldn't imagine they are not).
You also have to remember it's a high demand item which is slowly starting to come back into stock after the craziness from earlier this year. It might not be a lack of willingness to sell spare parts, but the simple fact they might not have them on hand to sell.
Experience is a cruel teacher, gives the exam first and then the lesson.