Wouldn’t leave a lot of shoulder left, .375 is the datum for a 6gt as shown here, but I suppose neither does a 300bo. Slow thumper.
.375+(.012*2)=0.399 of a reasonable outside neck diameter.
That leaves (.459-.399)/2=.030 of shoulder on each side, which is about twice as much as a black out.
Well, It is still in development, but this is what I like about it- standard bolt face, standard mags. I'm not entirely sure if I "need" a sub cartridge, but I already have a big bore can on order