Apparently the 22JGR is also a wildcat based on the 25ACP case like my 22 Epperson Cricket. Does anyone have any information on this version? Case dimensions, load recomendations? Apparently the JGR was done about 20 years ago. I've been loading the Cricket for 3 years now and am interested in anything similar.

I could be wrong but I thought the 22JGR was based on a .22 Hornet case? It was an extremely shortened (looked about as long as a 9mm)case with a bottleneck and the rim of the hornet had not been modified.

I've found reference to a rimmed and a semi-rimmed version of the JGR. But this source didn't say what the parent cases were. So you could be right on the rimmed version. The source I found was on a cartridge collector link and just didn't go into much detail.