FWIW, I found my chronographed data for the 4 5/8" Flattop in a post back in November 2011.
"The Keith load is 17.5 grains of 2400 under his 250 cast 429421. I have a 4 5/8" .44 Flattop and worked up from 14 to 16 grains and got good accuracy at each level, this was using that same 429421 bullet. Only chronographed them once but got the following results:
14.0 2400 - 977 fps
15.0 2400 - 1058 fps
16.0 2400 - 1126 fps
As you can see, 14.0 to 15.0 grains gives a decent mid to upper mid-range velocity. I never went above 16.0 as recoil got to be more than what I bought a .44 Special for.
Looking back over my targets, if I had to really recommend one level it would be 15.0 grains as those groups were a bit better overall than at 14 grains and velocity and recoil still was acceptable for extended shooting.Extrapolating those velocities it looks like 17.0/2400 would hit close on or at 1200 fps, but recoil even in the Bisley SA grip would be objectionable to say the least.
Oh well, gotta work with a new 38-55 for a while so playing with a new .44 revolver is something for the future. So many guns, so little time...
