The only people who are likely to know the answer are the guys that have fought them.

Ali said the hardest ever puncher he fought was Earnie Shavers.
Holmes said the hardest ever puncher he fought was Earnie Shavers.

Earnie may not have been able to land it every time he fought because he didnt have the speed and stamina to go along with the power. But the question is "Who is the Hardest Puncher", not "Who is the Best Puncher".

I go with 1) Shavers, 2) Foreman, 3) Max Baer, 4) Marciano, 5) Liston

All this is just guess work though. The only way we would know for sure is to get them to punch that machine that Ivan Drago punched in Rocky 4 !

PRESIDENT Boxing.org.uk