Most of my pet .44 Special loads utilize a 240 gr. cast SWC at 950~1000 fps. These for use in my converted Ruger Blackhawk (from a .357 Magnum) and my Ubertis.
I'd stay under the 1200 fps. range, though.
You're not going to blow up the gun, but such loads lead to excess battering from recoil, which shortens the life of a gun.