I believe that the 180gr SJHP UMC .44 magnums are rated at 1,600+ fps. A range-mate insists that he has chrono-ed them at 1650+ fps from a SBH. I recently shot a few from my 4" 629 MG - testing the new .500 Magnum Hogue backstrap-enclosing grips. So-equipped, it was highly shootable, albeit the muzzle rise was significant. My new 6" h-l 629, sporting those .500 Mag grips, was far better, with much less muzzle rise. Still, I prefer lower speed - and heavier - rounds... 240-300 gr; clad FP's, etc, at 900-1,000 fps is my 'idea' of a .44 Magnum.
Incidently, I chrono-ed my favorite .454 Casull 'thumpers' from my 7.5" SRH - those 240gr Hornady XTP's - and got 1,985 fps - yielding just less than 2,100 ft-lb KE -pretty substantial. Oddly, my .45 Schofield 'mild' loads, 200gr LRNFP over 4.5gr Titegroup for 700fps, make the same size hole in a piece of paper... sure don't 'ding' the plates as hard, of course!
Stainz