6.8 x 51 30degree, Longer neck in a SA Fwt - yeah I'd like that

No special tight twist is really required, because available bullets are designed for the normal 10" twist that millions of .270 Win work so well with. Change in that regard for the .277 caliber is going to be very slow. Glacial even.
On the other hand, a little over-stabilization isn't such a sin with todays quality of bullets. Lots of the new Lighter weight offerings designed for the SPC are available. Are they outside their performance envelope ?