I reload the .256 Win. Mag for a Ruger Hawkeye single shot pistol. I use brass made by Jamison (has a JBA headstamp) and Redding dies. Bullets are Hornady 60 grain flat points. Primers are Winchester Small Rifle. So far I have only used good old 2400 powder but that is mainly because of the scarcity of powder these days.

My reloading manuals only show the old standby's like Unique, Herco, H110, H4227 and 2400. But I would think that AA #7 and AA #9 would be good as they bracket 2400 and Hodgdon Lil'Gun also which is a bit faster than 4227 but slower than 2400 and AA #9 in burn rates.

There was an article in Handloader a few years back but I think it was using a Marlin Levermatic as the test gun. I can't find my copy but perhaps you can obtain a back issue from the publisher.