To start, I am a rookie when it comes to reloading. I am getting ready to load the Berger 156 Elite Hunter for my 6.5x284. I used the Hornady device to measure my distance to the the lands. It gave me a distance of 2.618” to the bullet ogive. I then thought I would try something I saw on YouTube to decide how much jump you need to load for. I loaded up a dummy load with the bullet seated way out. I colored the bullet with a magic marker, I then chambered it. When I got it out it measured 2.645” to the ogive and 2.566” to where the marker was messed up. My question is how can these two methods be so different?