I also use a fired case tapped and threaded by my gunsmith as well as doing that I measure 10 times and find the average that seems to helpI haven't used the stripped bolt method like in the Wheeler video but I plan to try it and compare the #'s to what I get with the Hornady tool. I always try and use consistent light pressure to push the bullet in so it doesn't manipulate my measurement #'s and I also take multiple measurements so I know I'm using the same amount of pressure to push the bullet up in till it touches. Also, I always have a case gauge made from a piece of brass that was fired in that particular chamber. I've tried using the modified case gauges from Hornady but they never seem to fit my chambers very tight and give me inconsistent and un-repeatable #'s so I just always have one made from fired brass shot in my specific gun.