Avoid head shots on dogs. They have varied jawbone structure and skull thickness per breed that makes it an uncertain shot. Behind the shoulder offers the largest area to hit, the greatest margin of error, and usually the most humane kill. If snaring is legal, then build a small pen to put scraps of meat and table fare into, with a conveniently placed hole under the fence. After letting them visit a few times, hang a snare in the hole. If you have a large enough area, and the material to do so, build it big enough to have several holes with snares. Its very effective! And the 17 will do just fine with a well placed shot.