That's true, he did say he used M855 ammo
EDIT:
A comment from a reader posted below the above linked article asked
Which is https://www.patreon.com/posts/buildi...date, Part Two"John, thanks for article. Does 77grain 5.56 change your conclusion? Does age of person cause you to reconsider 5.56? Thanks"
Nope. Nope. See this week’s article.