Glad to see old thread coming back from oblivion.
I have not tried to duplicate BB load with other powders. It's unlikely that they use 2400 or Lil'gun just because there was only 7.5 gr. of a powder in the case. It would probably take a lot more of a slow powder to get to this kind of velocities. A member of this forum JFH has a lot of experience with Ramshot powders. I know that he likes them and I trust his opinion and experience. Unique is a possibility but I don't think two 5's wouldn't cut it. According to Alliant manual (
link) 5.2 gr. Unique only gets you 919 fps from a 6-incher. I'd expect that it takes 6.5-7.0 gr. Unique to get 1000+ fps from a 2" bbl.
Thanks for nice comments
I am working on and off on a new project "Speer 135 grain load on steroids". Will eventually finish it off and post the results.
Cheers,
Mike