I'd be hard pressed to go FB on a 308 lengthed receiver...especially when 223/223AI brass is all but free. I'd be quick to use about 2.500" of the available 2.800" COAL and spin it 8".
The 77/22's beauty is in the modest length(when bobbed to 20"),mild mannerisms,eerie Precision and that spectacular Ruger OEM magazine.
