Thanks to Shooting The Messenger for this info.  Double Tap Ammo has a .357 magnum load that pushes a 200-grain bullet out of a 4-inch barrel at 1200 fps.  As tested in a 4-inch Ruger GP-100.

Or 1305 fps from a 6-inch barrel.

Makes me fantasize wonder what kind of muzzle velocity it would have from a rifle with a 20-inch barrel.

Check out this link for the full list of their .357 magnum ammo.

UPDATE:  In comments at his blog, Fits answers:
Double-Tap 125's do about 2350 fps from a 20".

Their 200's, a squeak above 1900.

At that velocity, the 125's can splatter, deform, and tumble upon penetration, not impact, but no one I know has tried them in gello. Water baggies and moistened newsprint, yes. Some are extricated pristine, others in pieces. This spring, we've plans to create a JayBox, with a friend in Iowa putting together an admiteddly Rube Goldberg setup whereby fresh rib bones can be suspended in water baggies. None of it will prove a damned thing except show what the rounds look like, but if they stay together reasonably well there are a few prepared to go hog hunting.