I like 4227 as it shoots very well and fills the case. But the downside is that the 20g loads eat the can of powder up pretty quickly (not to economical).
I was thinking about using IMR 4227, but couldn't find any data on it. I'll bet it has quite a huge muzzle blast!
Like shooting a 44 Mag! Do you also have any data on using H 4227? I think they are about the same. One of my favorite loads in 45 Colt is 10g Unique under a 255 Hardcast SWC for my Ruger BH 7 1/2" convertible.