I love my 6mm round, but would never use it toward a neighbor's property. If I were shooting into a hill, ok. If properly tuned, most of the current high-speed centerfires could do head shots on a yote at 200 yds.
I would second the advice to use a highly frangible bullet.
Another option is to go big and slow. I use a .44mag in a rifle for deer. That will do 150 yds but is dropping. It will be crawling along the ground before 1200 yds.
