I thought the same thing--and I'm pretty sure we're both right. They've made a few doubles in that cartridge, but I don't believe there were any around that far back in time. It's a bugger to get rimless cartridges to work in doubles, and took a while to perfect the technology. This chat group...
I called BS when he said that was the caliber because I always understood that to be a rimless cartridge that wasn't suitable for doubles. It was designed from the beginning to be used in bolt/magazine rifles. However, there are currently doubles in that chambering. Just not sure if there were...