Quote Originally Posted by HKGuns View Post
You can't buy them, so we may never know.

Maybe one of the .MIL guys who is on here can make some informed statements on this topic at some point.
If you have a suitably strong bolt action maybe you could get a custom barrel in .277 chambered for it?

I’ve read comments by some barrel makers stating they won’t warranty barrels used for .277 SIG if used with 80K PSI ammo though. Can’t blame them, useful throat life is probably going to be reduced quite a bit.