As the guy who has talked about a scaled up 365 XL as the “320 2.0” it will never happen. The Macro is as close as we are likely to see.
Gun companies exist to make money, not guns. The .MIL has 320s because SIG bid low on the MHS contract. They assessed (correctly) that winning the MHS contract would be a license to print money. That success is, in some ways a trap. SIG is not going to kill the golden goose.