I typically use a similar load but go with 8.0 grains of Unique, instead of 8.5 with the same bullet.
The last time I ran .45 LC and the Chronometer I was using my 4" Redhawk with the following load:
Caliber: .45 LC
Charge: 6.5 gr Solo 1250
Bullet: 255 gr RNL .452 S&S Casting
Primer: CCI 350
Velocity: 614 fps (6.3 SD)
Primer: CCI 300
Velocity: 599 fps (26.4 SD)
It had pretty poor accuracy but no recoil at all.
I'd probably get more accuracy out of this, my 6" Model 25-5.