When the first four Ramshot rifle powders made in Belgium appeared, around 20 years ago, Western didn't have a lot of loading data. And what they had worked up in their piezo-electronic pressure lab was naturally for more popular rifle cartridges.
As a result I figured out what commonly-listed powders were pretty close in burn-rate to TAC, Big Game, Hunter and Magnum, and use data for those other powders as starting point in less popular cartridges, and a chronograph as a general indication of pressure. Which is how I found out IMR4895 data provided a pretty good starting point for TAC, Winchester 760 for Big Game, Reloder 19 for Hunter, and H1000 for Magnum.
These days Hodgdon owns the Ramshot brands, and their 2023 burn-rate chart shows those comparisons are still pretty appropriate, though H4895 is listed as closer to TAC than IMR4895, and that data for H380 would also be pretty good for Big Game. And H380 data is often listed in other sources than Hodgdon.
Plus, the Internet provides a LOT more loading data these days, without having to rely on paper manuals.
