Is anyone seeing (this thread and another one dealing with pistol powders) that many Hodgdon and Winchester powders are the same?
That's because Hodgdon has never made a powder. All their powders are manufactured by someone else who puts the Hodgdon label on it.
Don
Bruce Hodgdon started as the retailer of a single surplus powder that was, I think, recovered from salvaged from 20mm shells.
And these days, Winchester is just a brand name - In fact, Hodgdon licenses the Winchester brand! Currently (and for some time past) ALL
ball powder is made by St. Marks Powder. There's no rule that says all ball powders with identical grain size and appearance are identical, however. Alliant 300MP (Also made by St. Marks) is VERY similar in appearance to H110/W296, but is noticeably flashier. It seems to be very slightly slower as well.
I spoke to a St. Marks chemist once, and he said that testing and liability issues favored fewer actual manufacturers and products, and that when they provide handbook load data, they intentionally do not report identical data for similar powders to avoid complacency. More recent load data seems to indicate that they no longer make that effort. He also told me that the reason nobody publishes pressure/time curves is because no two testing companies produce data that agrees, and that explaining the way that the test results are interpreted would be difficult at best, and grounds for litigation at worst.
Sorry, I'm feeling wordy today.