I just put together a Rem SA in 300W out of curiousity... couldnt get the spent cases to stay on the bolt past the breech end of the barrel without falling off? Seems to be purely question of length.
I got so angry I cut the bolt off and used a Savage bolt head in its place....Same scenario
Called PTG and they have a reamer for a 30 X 223
which is very close in capacity to the old 308 x 1.5 (Barnes) or .302 Whisper (SSK) .
The problem here may be OAL.... and dies, but in concept its sounding good if the mag box will take the length of the 30 cal boolets seated near the NS junction. May take going to the 7.62 X 39... I'll let y'all know when i figure it out.