My standard .44 Mag. load runs a 240 @ 1550, and a 300 @ 1400 fps from my 7 1/2" 83, and a bit more could be squeezed out if a person wanted to work at it.
Standard DW Super Mag loads don't better that by much, and many barely equal it ... and do it with that loooong cylinder. For the person who feels they want more velocity than the 83 .44 Mag. is capable of delivering, I suggest a .454.