tested in my 5.5" ss Redhawk
I found AA9 to give the best accuracy at higher velocities, but it's not for the fastest.
W296 worked well.
H110 worked a bit better, with highest velocities still balancing with decent accuracy.
For medium loads I found (once again) HS6 to be extremely accurate with very low deviations.
I use Universal Clays for my mediums; little less speed, very clean, economical, easy-metering.
And don't discount Alliant Power Pistol in the medium range.
"all my ammo is mostly retired factory ammo"