I didn't think about the twist rate, that makes sense. One more hurdle of different thinking that would need to happen.

I guess I should put my interest into context. I'm not really interested in super magnum ultra fast magnums for extreme long distance. I am thinking for the 375 H&H class. A 0.6-0.7 BC could extend the range that hunting bullets could reliably perform on game. For example, a 375 H&H would send a 300 gr accubond (bc .485) out around 2500 fps and drop below 2000 around 300 yds, which is starting to fall into questionable territory. It would be really nice to be able to reach to 400 with comfort that shooting skill is still the only challenge. Knowing that a 338 caliber accubond has a bc of .72 just eats away at me.

I know I may be looking for a way to have my cake and eat it too, but I have a wonder if these cartridges can have the flexibility like the 338 does. I hunting in Alaska with one rifle, at least one rifle per hunt. I love having my 375 for stuff less than 200 yards but you never know when the vegetation and terrain won't allow that.