We sell exportable muzzle brakes that are longer to meet minimum length requirements in Australia for the Covert rifles.
Orkan,
your astroid hope might come true today.

As far as a single chassis it would be clunky and heavy and not the streamlined system that you are used to. A 18 lb 308 would suck. Plus it would be very hard to get a mag to feed from a 50 caliber diameter bolt, actually very likely impossible, well maybe there are things that we could do, now that I think about it but it would take lots more parts and be very clunky and more expensive.