I'm definitely taking the .41 Short Rimfire.
Why? Everything else was taken, I don't want to have to compete at the counter for my ammo and also because the bullet moves SO SLOWLY that I can simply pick up all my slugs after shooting and DING - instant source of range lead without all the work to mine a berm.
Attention Brass rats and other reloaders: I really need .327 Federal Magnum brass, no lot size too small. Tell me what caliber you need and I'll see what I have to swap. PM me and we'll discuss.