Bad idea, IMHO.
I shoot at an indoor range. Thursday night is play night for the regulars. The range has a steel plate rack. One evening one of the guys shot himself in the leg -- a fragment from a FMJ 9mm bullet ricocheted off a plate and hit him in the calf. It wasn't life threatening, but it did require a trip to the ER and stitches.
IMHO 10 yards is too close, especially for something like .357 magnum.