IMR 4350 try Winchester 296 ball in your poppers.
I use H110 which is the pretty much if not same thing, but I've found 2400 to be more consistent.
I've been using a lot of AA#9 with a .44 spcl. It's stupid easy to get a good load (900-1000fps) without over pressure.
What are you using 296 in? I need to get a good load for a .44 mag. I'm using 4227 right now.
Great load, but experiment is the fun.