I started reloading .357 mag using IMR4227 some 50 years ago. The loads did exactly what I wanted and did what was predicted in the reloading manuals. The knock against IMR4227 was that was difficult to throw consistent weights thru any of the then available powder measures. As other powders came along that would go thru the powder measure easier and more accurately I stopped using IMR4227. With today's electronically automatic powder measures I would probably go back to using IMR4227. But with just a few years left for me to reload, I will just stick with my Redding Benchrest measure and other powders. ... Big Cholla