I have used the 6.5, 270, 30-06 and 7 mag. If you don’t shoot one in a kill spot then chances are you won’t find it. My son has killed 3 using a 6.5 and the furthest one ran was around 30 yards. A lot of folks don’t shoot before season and expect their equipment to function correctly. People kill deer with bows all the time. People have killed deer using 243 for years and the 6.5 has 200-300 ft. lbs more energy than the 243. It’s all about shot placement.