I have decided on kimber and maybe the 7mm-08. The 7mm-08 comes in a 22" length, the 270 in a 24" length and magnums come in 26". I don't understand the need for longer barrels. I will be shooting no longer than 300 yards but more than likely up to 200. In a 22" barrel will the 7mm-08 be an effective round or should I look into the 270 or 30.06, which both are in 24"? Keep in mind that this rifle is LIGHT and I will primarily be hunting whitetail.