I do find it odd that 300 WM, 300 PRC, 300 RUM, 300 Norma and even 300 WSM are mentioned, but there is no mention of the 30 Nosler. Maybe I’m biased, but 300 PRC requires CIP cut mag window and CIP length magazines. CIP lengths are more common now, but wasn’t a few years ago. 300 PRC is the longest 30 cal SAAMI spec round I’ve read about. The 300 Norma is an entirely different animal with the larger bolt face. Its like a baby 338 Lapua.
300 RUM is also out there but my buddy ran into mag length issues with heavier, high BC projectiles (unless my buddy throated 3 barrels incorrectly; I have no personal experience with the cartridge). He has 3 custom reamers and finally converted to 300 Norma. 300 RUM never shot excellent for him.
I will say the three 300 Norma’s Ive seen were cut from the same reamer and all shoot excellent. Very tight guns even from break in. One is even a factory Rem 700 action converted.
The 30 Nosler will drop into any 300 WM set-up (minus chambering of course). I went 30 Nosler years ago because the 300 PRC had not released. Once I read how long the cartridge was, it was too costly to convert even if I wanted to. I chose 30 Nosler over 300 WM to avoid the belted magnum brass (personally don’t care for a belted cartridge). I even have a laser 7 mag for hunting and still don't like the belted cartridge.
I’m running a 215 Berger with 80.3 gr H1000 at about 3,050-3,070 fps if I recall correctly. I’m satisfied there. Not chasing a 225 projectile or top tier velocities. I didn’t have a 30 cal magnum and chose 30 Nosler to avoid the 300 WM belted case.