I wish I had some more of my original Winchester .357 Mag. (circa 1940) ammo that I could send you for your J frame, BigG.
Of course you'd likely have to look around and find your gun, and hand, after every shot...
I chronographed this stuff some years ago out of a 6" Model 28.
158-gr. bullet moving at just shy of 1,700 fps -- out of a Six Inch tube!
8 3/8 probably would have gone close to 1,800 fps.
That's over 1,000 foot pounds of energy from a .357 Mag.
Today's load books don't even come close to that.
Some of my load books from the 1940s and 50s, though, do.