I have all the popular calibers, and not sure why, because when I go deer hunting, the 7mm08 with 140 gr bullets is what I use. The 243 will kill, and has taken many deer, but it is also responsible for many lost deer, when the bullet hits gut or bone. The bullet is too light. The 6.5 is the latest craze, but the bullet choice is not near as broad, and the 7mm bullet has proven itself for years. I have also used it in NRA Long Range Prone matches, with great success. It comes down to your decision, but for me, the 7mm08 is a deer killing machine.