Powerball does tend to be a shallow penetrator. For some reason my brain tells me that 100 gr. Powerball is a 9"-10" load. There may be gel results in the Test Bed forum an www.stoppingpower.net .

Corbon had a 90 gr. DPX load in the works designed around the Rohrbaugh pistol. X bullets penetrate nice and deep for their weight, so that load may be the hot ticket.