Re: Hornady Super Performance Powder
I can't help you on load data, though I seem to recall that Hodgdon may have a pdf file on their website that 'might' contain data for the 243...
In a phone call with a Hodgdon tech., they told me that Hornady has 40 different "blends" of this Superformance powder. All for different rounds.
Hodgdon just "picked one" and brought it to market. Per our phone conversation, it has a very narrow window where it surpasses existing powders for velocity.
Also, per my phone conversation, it is slightly slower in relative burn speed than H4831 (and is listed accordingly in Hodgdon's lates burn rate chart).
I plan to try some Superformance in my 30-280 Ackley Improved, as Hodgdon's technician thought it "just might work" in that round.