An interesting list I found written by Ben Cohen with history, quotes and opinions. I liked it because it agrred with my view on hardest puncher as Julian Jackson. Also, no list complete without Tommy "Hitman" Hearns.
1. Julian Jackson
Jackson’s power at 154-160lbs was absolutely freakish. Despite lacking elite boxing skill, the Virgin Island Middleweight tore his way through 55 opponents, knocking out 49 of them and winning several world titles on the way. His one punch knockout of Herol Graham was one of the best in boxing history, especially as Jackson was badly losing in their title bout in 1990. The almighty right hand that knocked Graham out before he hit the canvass has been replayed in every knockout compilation worth watching. Graham lay unconscious for 5 minutes after being caught, and was never really the same afterwards. Jackson’s ability to literally touch an opponent and hurt them meant he was always dangerous making every fight he was in a must watch event.
2. Earnie Shavers
Earnie Shavers was without a doubt the hardest punching heavyweight of all time. The American born bruiser wasn’t exactly the most refined of fighters, but his power was so extreme he could turn a fight around with one punch. For the most part, Shavers Most weighed under 210lbs suggesting the Liverpudlian based American could have fought at the modern day cruiserweight limit. He destroyed Ken Norton in one round, dropped Larry Holmes, and landed one of the hardest punches ever seen against Ron Lyle. Shavers right hand was the sort of punch the caused audiences to turn away when it landed. Both Holmes and Ali stated that Shavers hit them harder then anyone else, and given their combined resume, (Foreman, Tyson, Frazier, Liston), it would be hard to disagree.
3. Prince Naseem Hamed
After Hamed destroyed tough South African Vuyani Bungu in March of 2000, referee Joe Cortez stated that the Prince was the hardest punching featherweight he had ever seen. Weighing a mere 126lbs in his prime, Hamed’s power was nothing short of incredible. Not only did he have knock out power in both fists, the young Prince could generate fight-ending force from a bewildering array of angles. After clinically knocking out Augie Sanchez with some hammering blows in 2001, many ringsides could not believe that the diminutive Hamed did not have something in his gloves. His power was so amazing that his sparring partners regularly reported it being equal to that of a middleweight or above. Stories of bashing up heavyweights in his gym spread like wildfire, and coupled with some of the most awesome knockouts the featherweight division has ever seen, it would be fair to place Hamed’s power alongside the very best.
4. Tommy Hearns
Tommy Hearns was one of those rare fighters who managed to carry their power up through different weight categories. From 147 to 190lbs, Hearns possessed crunching power that could KO a fighter with one punch. Perhaps the most frightening display of his power came when he fought Roberto Duran at 154lbs. It was one of the most one-sided beatings ever seen between two great fighters, with Duran tasting the canvass three times. The final knockout came while Duran was pinned against the ropes where Hearns landed a right hand that would have felled most heavyweights. Duran was out before he hit the canvass, and the fight was promptly stopped. Hearns gangly 6ft1 frame was enormous, and the kinetic power he could generate was genuinely scary. As he filled out in weight, Hearns had no problem turning the extra pounds into extra force, retaining devastating power up to the cruiserweight division.
5. Sugar Ray Robinson
Not only was Ray Robinson one of the most skilled boxer of all time, he was one the best punchers as well. Lithe and slender, Robinson generated his power from his perfect technique. He pivoted on his feet, torqued his hips and maintained perfect posture while delivering pinpoint accurate punches. Robinson scored one-punch knockouts all the way from lightweight up to middleweight, proving that power was not just a product of muscle size. His most famous knockout came over the teak tough Gene Fullmer at middleweight. After losing a decision to Fullmer a few months earlier, Robinson landed the most perfect left hook ever landed in the 5th round of the rematch.
“I still don’t know anything about the punch,” Fullmer said years after the bout, “except I watched it on movies a number of times. The first thing I knew, I was standing up. I asked my manager, ‘What happened?’ and he said, ‘They counted ten.’ Up to then, I probably got to thinking I couldn’t be knocked out. And all at once, I realized that anybody can. It’s just got to be in the right place at the right time and you’re gone.”