Marty at Teppo Jutsu and I, have been discussing this thing for over a year now, but I finally got off my ass and finished it up. It's simply a rimmed version of Marty's original .458 SOCOM design. I formed some cases from 50 Alaskan, as well as from .348 Winchester cases and fired the rimmed version for the first time tonight through my suppressed Encore. It seemed to work just fine. We'll see how it fares at the range.
The Encore/Contender extractor design will not allow it to handle severely rebated rims much more than what's on the .284 case, hence the rim was required to get the SOCOM to fuction in the handgun.