Here's a link to an article that's worth reading:
A Special 44
I can't comment on AA9. However, I've used 5.0 grs Bullseye, 7.5 grs Unique and 15 grs of 2400 consistently in my N frame Smiths and Colt Single Action revolvers. This was behind 240/250 gr cast and 240 gr jacketed bullets.
With a 3" barrel you might want to stick to the first 2 lighter loads. Further, the Unique and 2400 loads are hotter than recommend in the Speer reloading manuals.
From what I've read, this is to protect older, more fragile revolvers. I would also be hesitant to use the hotter loads in small frame, lightweight revolvers.