i could be wrong but i always viewed them as one the jdj as maximizing rifles style cartridges out of a single shot versus GNR's which made very little sense to me as shooting big bore pistol cartridges out of pistols. if it were me and out of a contender/encore i'd go for the jdj cartridges b/c if i wanted to shoot the others it'd be out of a revolver and if i wanted to shoot cartridges out of a revolver i'd just stick with the standards as there's really no need for the GNR's as i see it. my humble opinion