Do you have the capacity in gr. of water to fill the case to the mouth?
I don't know what the .376 Styer capacity is, either.
My own .375/06IMP is 78gr. with RP or Fed. brass and 80gr. with WW brass.
Mine is more of an Arch chamber, rather than the slightly smaller Ackley Chamber.
You supposed ballistics are easily achieved in my .375, however, I only run the lighter 235's at 2,840fps.
Even that is just over 4,200fpe.