Have you tried W231
http://www.wwpowder.com/data/handgun/44swspec.php
I use it in a 624 3" with good results with 200gr Speer Gold Dot
Also works great for 265gr. GC lead in 44mag case 29-2 6.5", very clean at around 1000fps with excellent groups at 50yards provided I do my part. Works well for fast wild pigs around 150-200 lbs.
Also load it in .45acp for a 625 5".
I use 2400 for the higher magnum loads.