In one of the gun mags... probably Handloader, maybe Rifle as well. Seemed to get a decent write up for what that's worth.
I sent for literature, I remember they were expensive, relatively speaking, so I never bought any. They were one of (if not the only) source for .512" JHP's.... but I didn't have my 500L yet, it was still a dream then.
Oddly enough, I read mention of them just yesterday.... http://specialtypistols.infopop.cc/eve/forums/a/tpc/f/3646077864/m/8680050386
He wasn't thrilled with the ones they sent, or with how they ended. (I assume they're long out of business)
IIRC they offered the jackets in different thicknesses, so expansion/lack there of/over expansion probably depended a great deal on what your ordered.