SP = Spire Point
SPTZ= Spitzer bullet
NBT=Nosler or Norma boat tail bullet

and so on, the bullet type has a definite impact on accuracy....flat base bullets generally have a higher ballistic coefficient and have less gas cutting......

I see that the widest number of choices are in the 180 grain, that should tell you something about the 300 Weatherby chambering, based on it's fps vs. twist vs. bullet weight......

Best...

Doug