I am far from a legal guy, but they are allowing .40 cal ammo in a pistol, but it also has to be at least 1 1/16 inch long cartridge case. So the 40 S&W and the 10mm are less than 1 1/16 inch long so they would still be illegal. So I guess handgunners have gained nothing? The five rifle rounds picked seems crazy, but heck it is a start I guess. I hunt public land so I really gained nothing from all this.
If they name them, they would be an exception to the case length. Referencing some other posts on the 300, they also make a 300 WSM (Winchester Short Magnum) that uses a shorter larger diameter case, a 300 Weatherby Magnum as well as a few others. The 300 should stay as is and simply let it fly. The 300 B.O. is close to a 30.30 and plenty to take a deer. it is also one of the more popular calibers, it is a carbon copy of the 300 Whisper or the 300 Fireball. All use the same case, same bullet, with just enough difference in case length to keep the 3 from being able to sue each other. The 300 is already legal as a pistol, might as well leave it as is and then add a much better written version next year that clarifies mostly all calibers that should be legal without trying to name every cartridge.