You should not be using someone elses OAL!
You should be using your own OAL. Our OAL's have nothing to do with your rifle. OAL can affect pressure so you need test for your self. After your initial measurments you need to determine if you want to seat for magazine or not. If I seated for the magazine my bullets would be almost .10" away from the lands and at that point small variations should not make much diff.