My Wichita 10" single-shot pistol is chambered for 7mm Rimmed International, a wildcat created by necking down the .30-30 Winchester to 7mm with a 40-degree shoulder and minimal case taper. It's the predecessor by a few years to the popular 7-30 Waters cartridge.
It pushes a 140gr 7mm spitzer to 2000+ fps, but you really should wear shooting gloves.