The 243 and it's twin the 6mm Rem are great deer rounds, shoot the deer behind the shoulder, at the top of the heart, and deer fall over DRT. I found the old Speer 105g spitzer to be great deer medicine and got two elk with the same load. In all honesty, a 30-30 shooting 170g CoreLokt round nose bullets will kill deer as well up to about 150 yards and ruin less meat with a slightly off shot.