A third way is the simplest.Take a fired case,put a small dent in the neck so that a bullet can still be pushed into the neck with your finger.Barely seat a bullet in the case,place it in the chamber,and slowly close the bolt.Carefully remove the round and measure the overall length.Repeat several times until you obtain a consistant reading.Be aware that this dimension can vary for every bullet reguardless of style or weight.