I'm not a fan of rimless cartridges in the Cadet(any single shot, for that matter). For any of the .223 headsize cartridges,rimmed cases can be made.If too long for the more common cases, any of them can be made from 5.6x50R cases.The 5.6X50R is an excellent cartridge in its own right( I have taken Whitetail with mine, loaded with 60gr Partition bullets).Many years ago, Ross Sefried(sp?)spoke glowingly of an improved version of the 5.6 he had in a cadet.He compared it to factory 22-250, but I don't have any experience with this version.
Mike