This discussion has come up many times between myself and my friends once we started building ARs and putting old military rifles back together. The fact is that many explanations are just overly complex in the way that they present it or the polar opposite. Somehow there doesn’t seem to be any middle ground on this subject. Luckily, Hornady has put together a long list of videos that cover a multitude of subjects on their YouTube channel. Their hour long video on headspace is really what every reloader should watch to ensure that they fully know what is going on. Even though I grew up reloading there were many things in this video that helped me to make more sense out of the whole process.