IMR4227 works great in the 401 SLR, which is just about the big brother to the 41Mag.
I use 410 cast bullets as they are in mine, though the specs call for .406/.407 dia.
35 Remington cases formed and reloaded on standard 41Mag dies.
Burns clean in the auto loading action and functions fine.
Cast bullets in the 210 to 240 weight range get pushed out at about 2000fps +/-.
I use standard LR primers.
Should work fine in the 41Mag I'd think. Sounds like it does for some folks here! I wish I had tried it in mine when I owned it.