300 WSM is a better design in my opinion for a case, but they kind of screwed up the throat in the design. That is why all the factory ammo is 150-180 gr. Companies adapted to the screwed up throat design. Of course, when you throat for the ideal 200-215gr bullet, then it doesn't fit in the ~3" mags. It really needs a 3.2"-3.3" mag…what action is that? 270 WSM fits the mag, but still biased towards lighter bullets. Brass is also a problem. You have only Norma brass available. The others are so poorly made that they don't belong in this conversation.
300 WM is ok. Seems like throats and mags are in general alignment. Twists are often 10—12 twist, but really, 10-9 twist is a better range. Good brass is available. I haven't studied this one enough to know all the belt struggles that folks talk about, but I would guess those are more related to die & chamber design. That said, why put a belt on the case?? On a positive note, the belt helps positive ignition with short sized brass. I would also expect short sized brass to blow forward, held by the belt, instead of creating a thin brass wall near the 0.2" line, but I don't have experience here.
300 PRC….kind of the best of all. Better SAAMI throats. Generally barrels are 9 twist. Lapua and Peterson brass available. The mags are generally 3.6"…although CIP length might be better for VLD'S. No personal experience here, but folks complain about the die, chamber, brass fit at the base causing clickers
300 Sherman in a 3.43" mag.
@elkaholic does a lot to make simple Wildcats where brass, reamer and dies all work together harmoniously. FL Sizing is barely moving brass! Peterson, Starline both make brass. The only reason not to do this is if buying factory ammo is a require!
30 Sherman Mag….basically an improved PRC.