The 300 H&H was the original magnum 30 and while not as powerful as the rounds that followed it, it does have a classic elegance.  The rimmed (or flanged) version was designed for double rifles (or single shots) where a rim improves extraction reliability.  While the headstamp is not Bertram, it was made by Bertram to the same specifications.  The price is per 20 cases and the shipping weight is 365 g.