I’ve seen non-vital organ .243 shots drop them in their tracks (my kids were shooting).
.243 packs a punch. Speed is energy. I’ve seen lots of shots that hit major blood vessels and dropped deer in their tracks. I like eating the heart and liver, so I’ll aim over the heart. Sometimes get the lugs, sometimes right under the spine, taking out the aorta and the vena cava Shuts them down in an instant.