P.O Ackley's book has some load data, too- I'm sure whatever data Gibbs gave to Ackley. Most of that data scares the daylights out of me - developed before pressure testing equipment was commonly available, and Ackley took data from whatever sources he could get and reprinted it.
Back in those days, wildcatters were often really enthusiastic at the powder measure.
And Mauser actions were really cheap.