You can use 300 WSM data.
I should elaborate on this to support my assertion.
A while back gunsmith Charlie Sisk did an experiment where he chambered
the same barrel first to 300 H&H and then to 300 WSM. The barrel remained the same length forward of the case mouths, and that's the part of the length that counts toward velocity.
Pressure and velocity tests were performed and the the results were similar capacity + similar powder charge = similar pressure and velocity, the case shapes being markedly different showing no effect.
