My pick is the .218 Bee but brass is getting hard to find so I would suggest the .22 Hornet with the chamber reamed to K Hornet spec . Ruger and CZ both make nice rifles in standard Hornet and opening the chamber should not cost a lot but makes the cartridge MUCH easier to load . Use standard .22 Hornet and fire form to the K chamber . My favorite powder ( Win 680 ) is no longer available but AA1680 is basically the same and 12.5 gr of it or Littlegun lit by a small pistol primer gives very small groups in my m43 Winchester with Hornady 35 gr bullets . Great thing about the Hornets and the bee is you can load down to .22 Lr velocity for tree rats with cast or load up for larger game . The native people in Alaska used both for just about anything that walked from Seals to Polar Bears .

Eddie