I've used the 4227 for decades and never noticed unburned powder in my .44 mag loads. My recipe involves the Remington factory 240 gr JHP, a near max load of 4227 and the CCI LP magnum primer (350).

Trying to load this powder in other calibers where I didn't have the magnum primers did produce the unburned powder you describe. The magnum primer seems to be a necessity for clean burning.

I find the .44 load extremely accurate and effective. Somehow, I've never chrono'd the load. I flatly don't care how fast it's going. I know the trajectory, it's accurate, and anything I've shot it at ended up speedily dead with one round.