.357 is under a .40 caliber. Its a dumb arbitrary restriction, as the .357 clearly has more stopping power than a .40S&W, but that's what it is. So you can use your full sized glock, but not the 5 inch Ruger Blackhwak.

FWIW, I have a Blackhawk in 45LC. I killed a deer with it last fall at about 50 yards.