A 17 rimfire magnum would be fun. I see lots of them laying on the ground where I hunt.
If you reload the .223 with a 40 gr Ballistic Tip or V- Max at 3700 fps you will have lots of fun. My 220 Swift will throw the 50 gr as fast as a .223 will throw 40 gr. However the .220 Swift is loud and heats up fast and has more recoil. But if you like special effects it is your huckleberry! Before I owned a .220 Swift I had a 25-06 with 75 gr hp @3500 fps. It turned prairie dogs into three stage rockets!
Enjoy while it is still legal.
whelennut